Obtaining crystals and solving the phase problem remain major hurdles encountered by bio-crystallographers in their race to obtain new high-quality structures. Both issues can be overcome by the crystallophore, Tb-Xo4, a lanthanide-based molecular complex with unique nucleating and phasing properties. This article presents examples of new crystallization conditions induced by the presence of Tb-Xo4. These new crystalline forms bypass crystal defects often encountered by crystallographers, such as low-resolution diffracting samples or crystals with twinning. Thanks to Tb-Xo4's high phasing power, the structure determination process is greatly facilitated and can be extended to serial crystallography approaches.

Grazing-incidence small-angle X-ray scattering (GISAXS) coupled with computed tomography (CT) has enabled the visualization of the spatial distribution of nanostructures in thin films. 2D GISAXS images are obtained by scanning along the direction perpendicular to the X-ray beam at each rotation angle. Because the intensities at the q positions contain nanostructural information, the reconstructed CT images individually represent the spatial distributions of this information (e.g. size, shape, surface, characteristic length). These images are reconstructed from the intensities acquired at angular intervals over 180°, but the total measurement time is prolonged. This increase in the radiation dosage can cause damage to the sample. One way to reduce the overall measurement time is to perform a scanning GISAXS measurement along the direction perpendicular to the X-ray beam with a limited interval angle. Using filtered back-projection (FBP), CT images are reconstructed from sinograms with limited interval angles from 3 to 48° (FBP-CT images). However, these images are blurred and have a low image quality. In this study, to optimize the CT image quality, total variation (TV) regularization is introduced to minimize sinogram image noise and artifacts. It is proposed that the TV method can be applied to downsampling of sinograms in order to improve the CT images in comparison with the FBP-CT images.

The unique nucleating and phasing capabilities of the crystallophore, Tb-Xo4, are illustrated through challenging cases.

It’s not an exaggeration to say Hedrick was ecstatic when she peered into her inverted phase contrast microscope and found "Amphisolenia quadrispina" floating in her sample. “For 20 years I’ve been hoping to see something like this,” she says.

The post From the Bay of Bengal, a dinoflagellate makes its way to the Smithsonian appeared first on Smithsonian Insider.

The Smithsonian Astrophysical Observatory is a major partner in the Atmospheric Imaging Assembly, which is a group of four telescopes on NASA's Solar Dynamics Observatory that photograph the sun in 10 different wavelength bands, or colors, once every 10 seconds.

The post NASA’s new eye on the sun delivers stunning images appeared first on Smithsonian Insider.

Describing a species is a serious undertaking. In the case of T. acutus, Coats and his collaborators documented its microscopic life cycle, conducted extensive DNA analysis and unearthed scientific papers dating back to 1873—when parasitic dinoflagellates were first noted by German scientist Ernst Haeckel.

The post Introducing the parasitic dinoflagellate: Tintinnophagus acutus appeared first on Smithsonian Insider.

The National Aeronautics and Space Administration has made available to the public a new online collection of images that capture the excitement of planetary exploration and the journey to understand the origin and evolution of the solar system.

The post Stunning high-resolution NASA images available online for public exhibits appeared first on Smithsonian Insider.

A study published in the journal Global Change Biology finds that while fertilizer has been the dominant source of nitrogen pollution in Caribbean coastal ecosystems for the past 50 years, such pollution is on the decline, thanks in part to the introduction of more advanced, environmentally responsible agricultural practices during the last decade.

The post National Museum of Natural History’s coral collection used in Caribbean agricultural and sewage pollution study appeared first on Smithsonian Insider.

A description and photos of the green-headed tanager (Tangara seledon), a bird native to east-central South America, can be found in the Species of the […]

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Researchers from the Smithsonian Institution and the University of Florida have announced the discovery of a bone fragment, approximately 13,000 years old, in Florida with an incised image of a mammoth or mastodon.

The post Bone fragment is only Ice Age artwork from America to show a “proboscidean” appeared first on Smithsonian Insider.

The 5.8-magnitude earthquake that shook the eastern United States on the afternoon of Tuesday, Aug. 23, caused minor damage to some of the Smithsonian's natural history collections. All public Smithsonian museums are open and have been determined safe for visitors and staff.

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What Google is attempting for books, the University of California, Berkeley, plans to do for the world's vertebrate specimens: store them in "the cloud."

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A new study by a team of scientists from the Smithsonian’s National Museum of Natural History, the National University of Singapore and the Slovenian Academy of Sciences and Arts have unlocked the secret to mate binding in orb web spiders, and revealed just how it calms the cannibalistic female spider.

The post Suitor’s gentle massage soothes aggressive, cannibalistic female spiders, researchers find appeared first on Smithsonian Insider.

Ornithologists Carla Dove and Storrs Olson used 700- to 1,100-year-old feathers from a long extinct species of Hawaiian ibis to help determine the bird’s place in the ibis family tree. The feathers are the only known plumage of any of the prehistorically extinct birds that once inhabited the Hawaiian Islands.

The post Fossil feathers from a Hawaiian cave help reveal lineage of extinct, flightless ibis appeared first on Smithsonian Insider.

The image shows one of the most active and turbulent regions of star birth in our galaxy, a region called Cygnus X.

The post New Spitzer Space Telescope image shows space nursery appeared first on Smithsonian Insider.

This composite image from the Chandra X-ray Observatory (operated for NASA by the Smithsonian Astrophysical Observatory) shows the distribution of dark matter, galaxies, and hot […]

The post Chandra image of the core of the merging galaxy cluster Abell 520 appeared first on Smithsonian Insider.

To celebrate its 22nd anniversary in orbit, the Hubble Space Telescope has released a dramatic new image of the star-forming region 30 Doradus, also known […]

The post New image of the star-forming region 30 Doradus, also known as the Tarantula Nebula appeared first on Smithsonian Insider.

“The Age of Plastic: Ingenuity + Responsibility” a public Smithsonian Symposium that will take an uncommon look at the most common of materials. On Thursday, June […]

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Today, astronomers are releasing the highest-resolution images ever taken of the Sun's corona, or million-degree outer atmosphere, in an extreme-ultraviolet wavelength of light.

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Scientists at the University of Arizona and in California have completed the most challenging large astronomical mirror ever made.

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Small migratory male birds that winter in a stressful environment age faster than those that winter in a high-quality habitat, according to research stemming from […]

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This simulated image shows the Giant Magellan Telescope in operation in Chile while deploying lasers for its adaptive-optics system. The GMT is scheduled to begin […]

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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.

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.

Turtles have long been the subject of one the most contentious questions in evolutionary biology: where do they fit among vertebrates in the evolutionary tree […]

The post Turtle lineage solved in new study appeared first on Smithsonian Insider.

Defining what makes a star “Sun-like” is as difficult as defining what makes a planet “Earth-like.” A solar twin should have a temperature, mass, and […]

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In theory, crabs of the species Planes major should stay true to their mates for life. Heterosexual pairs of these small crustaceans live on loggerhead […]

The post Faithful crabs engage in risky behavior when opportunity arises appeared first on Smithsonian Insider.

From bizarre bugs to penis spines on bats, our world is infinitely expanded when we look down the microscope! Check out the stories behind these […]

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1. Centaurus A – A split-personality elliptical galaxy Centaurus A isn’t your typical elliptical galaxy. Its most striking feature is a dark dust lane across […]

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It is a simple solution to a wildlife water shortage. During the annual dry season [November through April] in a protected forest in eastern Cambodia, […]

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Like other kids at summer camp, a group of youngsters in the cities of Miami, Okla. and Fort Wayne, Ind. play games, work on crafts […]

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The collection of rocky planets orbiting distant stars has just grown by one, and the latest discovery is the most intriguing one to date. The […]

The post Astronomers Eager to Get a Whiff of Newfound Venus-like Planet appeared first on Smithsonian Insider.

The Giant Magellan Telescope Organization (GMTO) today announced that it has initiated the casting of the fifth of seven mirrors that will form the heart of […]

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Animal species can become endangered, but what about languages? Around 80 percent of the world’s population speaks just 20 percent of its 7,000 languages. That […]

The post Why languages become endangered, and how we can keep them alive appeared first on Smithsonian Insider.

When a natural disaster strikes, it devastates lives and homes, and can even destroy a culture’s identity and history. After a disaster, humanitarian response is […]

The post Protecting Puerto Rico’s heritage from another disaster appeared first on Smithsonian Insider.

Some of the earliest humans to inhabit America came from Europe according to a new book "Across Atlantic Ice: The Origin of America's Clovis Culture."

The post New book reveals Ice Age mariners from Europe were America’s first inhabitants 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.

Liza Botros MD., Manon C. A. Pronk PhD., Jenny Juschten MD., John Liddle, Sofia K. S. H. Morsing, Jaap D. van Buul PhD., Robert H. Bates, Pieter R. Tuinman MD. PhD., Jan S. M. van Bezu, Stephan Huveneers PhD., Harm Jan Bogaard MD. PhD., Victor W. M. van Hinsbergh PhD., Peter L. Hordijk PhD., and Jurjan Aman MD. PhD.

Aims: Endothelial barrier dysfunction leads to edema and vascular leak, carrying high morbidity and mortality. Previously, Abl kinase inhibition was shown to protect against vascular leak. Using the distinct inhibitory profiles of clinically available Abl kinase inhibitors, we aimed to provide a mechanistic basis for novel treatment strategies against vascular leakage syndromes.

Methods & Results: Bosutinib most potently protected against inflammation-induced endothelial barrier disruption. In vivo, bosutinib prevented LPS-induced alveolar protein extravasation in an acute lung injury mice model. Mechanistically, Mitogen-activated Protein 4 Kinase 4 (MAP4K4) was identified as important novel mediator of endothelial permeability, which signals via ezrin, radixin and moesin proteins to increase turnover of integrin-based focal adhesions. The combined inhibition of MAP4K4 and Arg by bosutinib preserved adherens junction integrity and reduced turnover of focal adhesions, which synergistically act to stabilize the endothelial barrier during inflammation.

Conclusion: MAP4K4 was identified as important regulator of endothelial barrier integrity, increasing focal adhesion turnover and disruption of cell-cell junctions during inflammation. Inhibiting both Arg and MAP4K4, the clinically available drug bosutinib may form a viable strategy against vascular leakage syndromes.

Aline A. Alves, Heloisa B. Gabriel, Maria J. R. Bezerra, Wanderley de Souza, Sue Vaughan, Narcisa L. Cunha-e-Silva, and Jack D. Sunter

Eukaryotic flagella are complex microtubule based organelles and in many organisms there are extra-axonemal structures present, including the outer dense fibres of mammalian sperm and the paraflagellar rod (PFR) of trypanosomes. Flagellum assembly is a complex process occurring across three main compartments, the cytoplasm, the transition fibre-transition zone, and the flagellum. It begins with translation of protein components, followed by their sorting and trafficking into the flagellum, transport to the assembly site and then incorporation. Flagella are formed from over 500 proteins; the principles governing axonemal component assembly are relatively clear. However, the coordination and sites of extra-axonemal structure assembly processes are less clear.

We have discovered two cytoplasmic proteins in T. brucei that are required for PFR formation, PFR assembly factors 1 and 2. Deletion of either PFR-AF1 or PFR-AF2 dramatically disrupted PFR formation and caused a reduction in the amount of major PFR proteins. The presence of cytoplasmic factors required for PFR formation aligns with the concept of processes occurring across multiple compartments to facilitate axoneme assembly and this is likely a common theme for extra-axonemal structure assembly.

Great white sharks, killer whales, sea lions, even polar bears—the ocean is full of giant predators. But one of the ocean’s worst enemies is not […]

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Dr. Mary Hagedorn, a marine biologist at the Smithsonian Institution, talks about her research to understand and conserve our oceans' corals.

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Dr. Mary Hagedorn, a marine biologist at the Smithsonian Institution, talks about her research to understand and conserve our oceans' corals. To meet more scientists, visit https://insider.si.edu.

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The post Learn about the National Zoo’s flamingo flock with keeper Sara Hallager appeared first on Smithsonian Insider.

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.

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 Japanese acrobats ca. 1927, footage from the Smithsonian’s Human Studies Film Archive appeared first on Smithsonian Insider.

Meet Rachel Page, a Smithsonian scientist in Panama who studies frog-eating bats (fringe-lipped bats), among other topics. Her current research focuses on learning and memory in neotropical bats, combining field studies with laboratory experiments to learn about predator cognition and its effects on the evolution of their prey.

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