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‘The Wrong Wrights’: A Graphic Novel from Smithsonian Books

In the first volume of the Secret Smithsonian Adventures graphic-novel series from Smithsonian Books, The Wrong Wrights, four middle-school kids visit the Smithsonian’s National Air […]

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SNAP29 mediates the assembly of histidine-induced CTP synthase filaments in proximity to the cytokeratin network [RESEARCH ARTICLE]

Archan Chakraborty, Wei-Cheng Lin, Yu-Tsun Lin, Kuang-Jing Huang, Pei-Yu Wang, Yi-Feng Chang, Hsiang-Iu Wang, Kung-Ting Ma, Chun-Yen Wang, Xuan-Rong Huang, Yen-Hsien Lee, Bi-Chang Chen, Ya-Ju Hsieh, Kun-Yi Chien, Tzu-Yang Lin, Ji-Long Liu, Li-Ying Sung, Jau-Song Yu, Yu-Sun Chang, and Li-Mei Pai

Under metabolic stress, cellular components can assemble into distinct membraneless organelles for adaptation. One such example is cytidine 5'-triphosphate synthase (CTPS), which forms filamentous structures under glutamine deprivation. We have previously demonstrated that histidine (His)-mediated methylation regulates the formation of CTPS filaments to suppress enzymatic activity and preserve the CTPS protein under Gln deprivation, which promotes cancer cell growth after stress alleviation. However, it remains unclear where and how these enigmatic structures are assembled. Using CTPS-APEX2-mediated in vivo proximity labeling, we found that SNAP29 regulates the spatiotemporal filament assembly of CTPS along the cytokeratin network in a keratin 8 (KRT8)-dependent manner. Knockdown of synaptosome-associated protein 29 (SNAP29) interfered with assembly and relaxed the filament-induced suppression of CTPS enzymatic activity. Furthermore, APEX2 proximity labeling of keratin 18 (KRT18) revealed a spatiotemporal association of SNAP29 with cytokeratin in response to stress. Super-resolution imaging suggests that during CTPS filament formation, SNAP29 interacts with CTPS along the cytokeratin network. This study links the cytokeratin network to the regulation of metabolism by compartmentalization of metabolic enzymes during nutrient deprivation.




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Mitochondrial-nuclear heme trafficking is regulated by GTPases in control of mitochondrial dynamics and ER contact sites [RESEARCH ARTICLE]

Osiris Martinez-Guzman, Mathilda M. Willoughby, Arushi Saini, Jonathan V. Dietz, Iryna Bohovych, Amy E. Medlock, Oleh Khalimonchuk, and Amit R. Reddi

Heme is a cofactor and signaling molecule that is essential for much of aerobic life. All heme-dependent processes in eukaryotes require that heme is trafficked from its site of synthesis in the mitochondria to hemoproteins located throughout the cell. However, the mechanisms governing the mobilization of heme out of the mitochondria, and the spatio-temporal dynamics of these processes, are poorly understood. Herein, using genetically encoded fluorescent heme sensors, we developed a live cell assay to monitor heme distribution dynamics between the mitochondrial inner-membrane, where heme is synthesized, and the mitochondrial matrix, cytosol, and nucleus. Surprisingly, heme trafficking to the nucleus is ~25% faster than to the cytosol or mitochondrial matrix, which are nearly identical, potentially supporting a role for heme as a mitochondrial-nuclear retrograde signal. Moreover, we discovered that the heme synthetic enzyme, 5-aminolevulinic acid synthase (ALAS), and GTPases in control of the mitochondrial dynamics machinery, Mgm1 and Dnm1, and ER contact sites, Gem1, regulate the flow of heme between the mitochondria and nucleus. Overall, our results indicate that there are parallel pathways for the distribution of bioavailable heme.




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Chondrosarcoma-associated gene 1 (CSAG1) maintains the integrity of the mitotic centrosome in cells with defective p53 [RESEARCH ARTICLE]

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.




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Automated 3D light-sheet screening with high spatiotemporal resolution reveals mitotic phenotypes [TOOLS AND RESOURCES]

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.




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Kinesin-14s and microtubule dynamics define fission yeast mitotic and meiotic spindle assembly and elongation [RESEARCH ARTICLE]

Ana Loncar, Sergio A. Rincon, Manuel Lera Ramirez, Anne Paoletti, and Phong T. Tran

To segregate the chromosomes faithfully during cell division, cells assemble a spindle that captures the kinetochores and pulls them towards opposite poles. Proper spindle function requires correct interplay between microtubule motors and non-motor proteins. Defects in spindle assembly or changes in spindle dynamics are associated with diseases like cancer or developmental disorders. Here we compared mitotic and meiotic spindles in fission yeast. We show that even though mitotic and meiotic spindles undergo the typical three phases of spindle elongation, they have distinct features. We found that the relative concentration of kinesin-14 Pkl1 is decreased in meiosis I compared to mitosis, while the concentration of kinesin-5 Cut7 remains constant. We identified the second kinesin-14 Klp2 and microtubule dynamics as factors necessary for proper meiotic spindle assembly. This work defines differences between mitotic and meiotic spindles in fission yeast, and provides prospect for future comparative studies.




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A new brain mitochondrial sodium-sensitive potassium channel: effect of sodium ions on respiratory chain activity [RESEARCH ARTICLE]

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.




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With 1844 first edition, Smithsonian Libraries completes its collection of Charles Darwin’s three-volume geology series

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.

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Smithsonian’s National Gem Collection acquires a yellow fluorite from Tanzania

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.

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Smithsonian Digital Repository Now Contains 10,000 Items

The Smithsonian Research Online program recently surpassed the mark of 10,000 publications in the Digital Repository. This collection of digital publications by Smithsonian staff represents a broad review of research done by researchers at the Institution.

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Smithsonian hydrologist discovers that rainfall has dried up Panama’s drinking water

To understand the long-term effects of a prolonged tropical storm in the Panama Canal watershed, Robert Stallard, staff scientist at the Smithsonian Tropical Research Institute and research hydrologist at the U.S. Geological Survey, and Armando Ubeda, the LightHawk Mesoamerica program manager, organized four flights over the watershed to create a digital map of landslide scars.

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Q&A: Smithsonian volcanologist Richard Wunderman answers questions about the Aug. 23, East Coast earthquake

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 […]

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A hot new island has just surfaced in the Red Sea. What’s going on? Smithsonian scientists explain.

The new island visible in the satellite photograph is the top of a giant shield volcano located on the rift axis in the Red Sea where the continental plates of Africa and Arabia are pulling apart.

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Magnificent Dom Pedro aquamarine to go on view in the Smithsonian’s Natural History Museum

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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NASA, Smithsonian renew hunt for Antarctic meteorites

NASA, the National Science Foundation and the Smithsonian recently renewed their agreement to search for, collect and curate Antarctic meteorites in a partnership known as […]

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Microplastics in our environment: A conversation with Odile Madden, Smithsonian plastics scientist

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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A clouded leopard cub, a Przewalski’s horse and a red panda cub were all recently born at the Smithsonian’s National Zoo

As you read here
In a 24-hour-period between July 9 and 10, 2009 a clouded leopard cub, a Przewalski's horse, and a red panda cub were all born at Smithsonian's National Zoo's Conservation and Research Center in Front Royal, Virginia.

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Flesh Eating beetles help prepare skeletons for study at the Smithsonian’s Natural History Museum

John Ososky, preparator in the Osteology Laboratory at the Smithsonian's National Museum of Natural History in Washington, D.C., explains how skeletons of animal specimens are prepared for exhibtion and for study—with the assistance of nearly 1 million flesh-eating beetles.

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Antarctic Treaty Summit, Nov. 30-Dec. 3, 2009, Smithsonian, Washington, D.C.

"The Antarctic Treaty Summit: Science-Policy Interactions in International Governance" will be convened at the Smithsonian Institution, National Museum of Natural History in Washington, DC from Nov. 30 to Dec. 3 2009. More information on this event can be found at the Web site: www.atsummit50.aq/

To assess legacy lessons about managing nearly 10% of the Earth "for peaceful purposes only"

Find out how you can be involved:

www.atsummit50.aq

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Smithsonian team examines African remains from a colonial burial site in Maryland

Forensic anthropologists from the Smithsonian's National Museum of Natural History discover African remains at a Colonial burial site in Maryland. Follow them as they study the remains, reconstruct the face and body, and share what they learn about the African experience in the Chesapeake in the 1600s.

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Smithsonian geophysicist Bruce Campbell explains his work of making a detailed radar map of the Moon

Bruce Campbell, of the Center for Earth and Planetary Studies at the Smithsonian's National Air and Space Museum, is at the National Radio Astronomy Observatory in Green Bank, W. Va., to make a radar map of the Moon.

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The science of panda cubs at the Smithsonian Conservation Biology Institute

When animal care staff at the Smithsonian's National Zoo need to know when to breed their pandas or when to expect a cub they turn to the Endocrine (Hormones) Research Lab at the Zoo's Front Royal, Va. facility.

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Smithsonian volcanologist Rick Wunderman talks about volcanos and the recent eruptions in Iceland

Rick Wunderman of the Global Volcanism Program at the Smithsonian's National Museum of Natural History talks about the current volcanic activity in Iceland.

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Meet Our Scientist: Dr. JoGayle Howard of the Smithsonian’s National Zoological Park

Dr. JoGayle Howard of the Smithsonian's National Zoo discusses her work to breed and study one of the world's most endangered cats, the clouded leopard. More about the National Zoo's work to save clouded leopards: http://nationalzoo.si.edu/SCBI/ReproductiveScience/ConsEn...
http://nationalzoo.si.edu/support/annualappeal/cloudedleo... ... (more info)

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Smithsonian entomologist Gary Hevel gives information and advice about stinkbugs in your home

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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Device at the Smithsonian Environmental Research Center examines how phytoplankton would react if the ozone layer vanished

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





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Many years of research are celebrated in the December 2010 birth of two cheetah cubs at the Smithsonian Conservation Biology Institute

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Roland Kays, curator of mammals at the New York State Museum, discusses a new Smithsonian Website for sharing camera-trap images of wild animals

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.






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Smithsonian geologist Liz Cottrell talks about what it takes to be a scientist.

Which is more important for a career as a scientist, good grades in math or a strong sense of adventure? Hear what Smithsonian geologist Liz Cottrell has to say as she recounts her own school years and the steps that led to a career she can't imagine ever giving up.

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Smithsonian biologist Rachel Collin visits the Universidad Austral de Chile to collect special snails for her research.

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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Hand-rearing clouded leopard cubs at the Smithsonian Conservation Biology Institute

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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Kari Bruwelheide, forensic anthropologist at the Smithsonian’s National Museum of Natural History, discusses the power of bones.

Kari Bruwelheide, forensic anthropologist at the Smithsonian's National Museum of Natural History, discusses how she came to work at the museum, the power of human remains and the information that bones can contain. She and her colleagues continue to discover new ways to interpret evidence from bones and burials.

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  • Video
  • National Museum of Natural History

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Meet Our Scientist: Matthew Carrano, curator of dinosauria at the Smithsonian’s National Museum of Natural History

Meet the Smithsonian's Matthew Carrano, curator of Dinosauria at the Smithsonian's National Museum of Natural History in Washington, D.C. Matthew studies all things dinosaur, but focuses on the evolutionary history of predatory (meat eating) dinosaurs.

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Meet Our Scientist: Justin Touchon, Frog Follower at the Smithsonian Tropical Research Institute in Panama

Meet Smithsonian scientist Justin Touchon, a National Science Foundation (NSF) postdoctoral researcher at the Smithsonian Tropical Research Institute in Panama.

Justin's work focuses on developmental ecology and reproductive plasticity of the hourglass treefrog (Dendropsophus ebraccatus) and red-eyed treefrog (Agalychnis callidryas). Justin and his advisor, Karen Warkentin, were the first to have witnessed the frogs laying eggs in water, in addition to doing so on land -- something with major implications for the evolutionary biology of similar creatures.

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