The next generation of the Sloan Digital Sky Survey (SDSS-V), directed by Juna Kollmeier of the Carnegie Institution for Science, will move forward with mapping […]

The post Next generation astronomical survey to map the entire sky appeared first on Smithsonian Insider.

Astronomers had a mystery on their hands. No matter where they looked, from inside the Milky Way to distant galaxies, they observed a puzzling glow […]

The post GBT Detection Unlocks Exploration of ‘Aromatic’ Interstellar Chemistry appeared first on Smithsonian Insider.

Every queen deserves a castle, and the ruler of the Smithsonian’s National Zoo’s naked mole-rat colony is no different. After 27 years in a maze […]

The post Building a naked mole-rat dream home at the Smithsonian’s National Zoo appeared first on Smithsonian Insider.

The outer membrane of Gram-negative bacteria is highly impermeable to hydrophilic molecules of larger than 600 Da, protecting these bacteria from toxins present in the environment. In order to transport nutrients across this impermeable membrane, Gram-negative bacteria utilize a diverse family of outer-membrane proteins called TonB-dependent transporters. The majority of the members of this family transport iron-containing substrates. However, it is becoming increasingly clear that TonB-dependent transporters target chemically diverse substrates. In this work, the structure and phylogenetic distribution of the TonB-dependent transporter YncD are investigated. It is shown that while YncD is present in some enteropathogens, including Escherichia coli and Salmonella spp., it is also widespread in Gammaproteobacteria and Betaproteobacteria of environmental origin. The structure of YncD was determined, showing that despite a distant evolutionary relationship, it shares structural features with the ferric citrate transporter FecA, including a compact positively charged substrate-binding site. Despite these shared features, it is shown that YncD does not contribute to the growth of E. coli in pure culture under iron-limiting conditions or with ferric citrate as an iron source. Previous studies of transcriptional regulation in E. coli show that YncD is not induced under iron-limiting conditions and is unresponsive to the ferric uptake regulator (Fur). These observations, combined with the data presented here, suggest that YncD is not responsible for the transport of an iron-containing substrate.

Pullulanase (EC 3.2.1.41) is a well known starch-debranching enzyme that catalyzes the cleavage of α-1,6-glycosidic linkages in α-glucans such as starch and pullulan. Crystal structures of a type I pullulanase from Paenibacillus barengoltzii (PbPulA) and of PbPulA in complex with maltopentaose (G5), maltohexaose (G6)/α-cyclodextrin (α-CD) and β-cyclodextrin (β-CD) were determined in order to better understand substrate binding to this enzyme. PbPulA belongs to glycoside hydrolase (GH) family 13 subfamily 14 and is composed of three domains (CBM48, A and C). Three carbohydrate-binding sites identified in PbPulA were located in CBM48, near the active site and in domain C, respectively. The binding site in CBM48 was specific for β-CD, while that in domain C has not been reported for other pullulanases. The domain C binding site had higher affinity for α-CD than for G6; a small motif (FGGEH) seemed to be one of the major determinants for carbohydrate binding in this domain. Structure-based mutations of several surface-exposed aromatic residues in CBM48 and domain C had a debilitating effect on the activity of the enzyme. These results suggest that both CBM48 and domain C play a role in binding substrates. The crystal forms described contribute to the understanding of pullulanase domain–carbohydrate interactions.

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.

Laura O'Regan, Giancarlo Barone, Rozita Adib, Chang Gok Woo, Hui Jeong Jeong, Emily L. Richardson, Mark W. Richards, Patricia A.J. Muller, Spencer J. Collis, Dean A. Fennell, Jene Choi, Richard Bayliss, and Andrew M. Fry

EML4-ALK is an oncogenic fusion present in ~5% non-small cell lung cancers. However, alternative breakpoints in the EML4 gene lead to distinct variants with different patient outcomes. Here, we show in cell models that EML4-ALK variant 3 (V3), which is linked to accelerated metastatic spread, causes microtubule stabilization, formation of extended cytoplasmic protrusions and increased cell migration. It also recruits the NEK9 and NEK7 kinase to microtubules via the N-terminal EML4 microtubule-binding region. Overexpression of wild-type EML4 as well as constitutive activation of NEK9 also perturb cell morphology and accelerate migration in a microtubule-dependent manner that requires the downstream kinase NEK7 but not ALK activity. Strikingly, elevated NEK9 expression is associated with reduced progression-free survival in EML4-ALK patients. Hence, we propose that EML4-ALK V3 promotes microtubule stabilization through NEK9 and NEK7 leading to increased cell migration. This represents a novel actionable pathway that could drive metastatic disease progression in EML4-ALK lung cancer.

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.

Olga Kopach, Noemi Esteras, Selina Wray, Dmitri A. Rusakov, and Andrey Y. Abramov

Frontotemporal dementia and parkinsonism (FTDP-17) caused by the 10+16 splice-site mutation in the MAPT provides an established platform to model tau-related dementia in vitro. Human iPSC-derived neurons have been shown to recapitulate the neurodevelopmental profile of tau pathology during in vitro corticogenesis as in the adult human brain. However, the neurophysiological phenotype of these cells has remained unknown, leaving unanswered questions over the functional relevance and the gnostic power of this disease model. Here we used electrophysiology to explore the membrane properties and intrinsic excitability of the generated neurons to find that human cells mature by ~150 days of neurogenesis to become compatible with matured cortical neurons. In earlier FTDP-17, neurons, however, exhibited a depolarized resting membrane potential associated with increased resistance and reduced voltage-gated Na⁺- and K⁺-channel-mediated conductance. The Na_v1.6 protein was reduced in FTDP-17. These led to a reduced cell capability of induced firing and changed action potential waveform in FTDP-17. The revealed neuropathology may thus contribute to the clinicopathological profile of the disease. This sheds new light on the significance of human models of dementia in vitro.

M. Pinar and M. A. Penalva

TRAnsport Protein Particle (TRAPP) complexes regulate membrane traffic. TRAPPII and TRAPPIII share a core hetero-heptamer, also denoted TRAPPI. In fungi TRAPPIII and TRAPPII mediate GDP exchange on RAB1 and RAB11, respectively, regulating traffic across the Golgi, with TRAPPIII also activating RAB1 in autophagosomes. Our finding that Aspergillus nidulans TRAPPII can be assembled by addition of a TRAPPII-specific subcomplex onto core TRAPP prompted us to investigate the possibility that TRAPPI/TRAPPIII already residing in the Golgi matures into TRAPPII to determine a RAB1-to-RAB11 conversion as Golgi cisternae progress from early Golgi to TGN identity. By time-resolved microscopy we determine that the TRAPPII reporter Trs120/TRAPPC9 is recruited to existing TGN cisternae slightly before RAB11 arrives, and resides for~45 sec on them before cisternae tear off into RAB11 secretory carriers. Notably, the core TRAPP reporter Bet3/TRAPPC3 was not detectable in early Golgi cisternae, being instead recruited to TGN cisternae simultaneously with Trs120/TRAPPC9, indicating en bloc recruitment of TRAPPII to the Golgi and arguing strongly against the TRAPP maturation model.

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.

Westley Heydeck, Brian A. Bayless, Alexander J. Stemm-Wolf, Eileen T. O'Toole, Amy S. Fabritius, Courtney Ozzello, Marina Nguyen, and Mark Winey

Basal bodies (BBs) are microtubule-based organelles that template and stabilize cilia at the cell surface. Centrins ubiquitously associate with BBs and function in BB assembly, maturation, and stability. Human POC5 (hPOC5) is a highly conserved centrin-binding protein that binds centrins through Sfi1p-like repeats and is required for building full-length, mature centrioles. Here, we use the BB-rich cytoskeleton of Tetrahymena thermophila to characterize Poc5 BB functions. Tetrahymena Poc5 (TtPoc5) uniquely incorporates into assembling BBs and is then removed from mature BBs prior to ciliogenesis. Complete genomic knockout of TtPOC5 leads to a significantly increased production of BBs yet a markedly reduced ciliary density, both of which are rescued by reintroduction of TtPoc5. A second Tetrahymena POC5-like gene, SFR1, is similarly implicated in modulating BB production. When TtPOC5 and SFR1 are co-deleted, cell viability is compromised, and levels of BB overproduction are exacerbated. Overproduced BBs display defective transition zone formation and a diminished capacity for ciliogenesis. This study uncovers a requirement for Poc5 in building mature BBs, providing a possible functional link between hPOC5 mutations and impaired cilia.

Stephen Kershaw, David J. Morgan, James Boyd, David G. Spiller, Gareth Kitchen, Egor Zindy, Mudassar Iqbal, Magnus Rattray, Chris M. Sanderson, Andrew Brass, Claus Jorgensen, Tracy Hussell, Laura C. Matthews, and David W. Ray

Glucocorticoids (GCs) act through the glucocorticoid receptor (GR) to regulate immunity, energy metabolism, and tissue repair. Upon ligand binding, activated GR mediates cellular effects by regulating gene expression, but some GR effects can occur rapidly without new transcription. We show GCs rapidly inhibit cell migration, in response to both GR agonist and antagonist ligand binding. The inhibitory effect on migration is prevented by GR knockdown with siRNA, confirming GR specificity, but not by actinomycin D treatment, suggesting a non-transcriptional mechanism. We identified a rapid onset increase in microtubule polymerisation following glucocorticoid treatment, identifying cytoskeletal stabilisation as the likely mechanism of action. HDAC6 overexpression, but not knockdown of αTAT1, rescued the GC effect, implicating HDAC6 as the GR effector. Consistent with this hypothesis, ligand-dependent cytoplasmic interaction between GR and HDAC6 was demonstrated by quantitative imaging. Taken together, we propose that activated GR inhibits HDAC6 function and thereby increases the stability of the microtubule network to reduce cell motility. We therefore report a novel, non-transcriptional mechanism whereby GCs impair cell motility through inhibition of HDAC6 and rapid reorganization of the cell architecture.

During a press conference Friday, July 22 at the Smithsonian's National Air and Space Museum, NASA announced that Gale Crater will be the landing site for the Mars Science Laboratory. Scheduled to launch in late 2011 and arrive at Mars in August 2012, the Mars Science Laboratory is a rover that will assess the planet’s “habitability”—if it ever was, or is today, an environment able to support microbial life.

The post Gale Crater to be landing site for NASA’s Mars Science Laboratory appeared first on Smithsonian Insider.

More than 500 carats of rough diamonds were recently donated to the Department of Mineral Sciences of the Smithsonian’s Natural History Museum by Jewlers Mutual Insurance Co. of Neenah, Wis.

The post 500 carats of rough diamonds donated to Natural History Museum appeared first on Smithsonian Insider.

Recent airborne geophysical surveys near Decorah, Iowa are providing an unprecedented look at a 470-million-year-old meteorite crater concealed beneath bedrock and sediments. The aerial surveys, […]

The post Iowa meteorite crater confirmed appeared first on Smithsonian Insider.

Researchers at the Smithsonian's National Zoo's new genetics lab use animal DNA to diagnose new diseases, discover new species help in conservation efforts and solve mysteries.

The post Scientists at a new National Zoo laboratory use DNA to diagnose illnesses and discover new species of animals appeared first on Smithsonian Insider.

Join National Zoo Conservation Biologist Brian Gratwicke in his work to save Panama's amphibians from extinction. You can also catch up on his dispatches from the field on the Panamanian Amphibian Rescue and Conservation Project's blog: http://amphibianrescue.org/

The post Meet our Scientist: Brian Gratwicke, Amphibian Avenger appeared first on Smithsonian Insider.

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

The post Great Cats curator Craig Saffoe discusses his work caring for the National Zoo’s seven frisky lion cubs appeared first on Smithsonian Insider.

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

This new PBS Newshour video takes a look at a new exhibit at the Air and Space Museum celebrating NASA's space art program.

The post PBS Newshour takes a look at the new National Air and Space Museum exhibition “NASA | ART: 50 Years of Exploration” appeared first on Smithsonian Insider.

Keepers at the Smithsonian's National Zoo perform an artificial insemination procedure on a pair of Stanley Cranes. A Stanley Crane chick was successfully hatched on May 23, 2011.

The post Bird keepers at the National Zoo demonstrate the art of artificially inseminating Stanley cranes appeared first on Smithsonian Insider.

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.

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.

The post Meet Our Scientist: Matthew Carrano, curator of dinosauria at the Smithsonian’s National Museum of Natural History appeared first on Smithsonian Insider.

The post How do paleontologists identify dinosaur teeth? Smithsonian Curator Matthew Carrano identifies Cretaceous dinosaur teeth from the Washington D.C. area. appeared first on Smithsonian Insider.

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 Natural History Museum curator Nick Pyenson explains how scientists know what dinosaurs and other extinct animals ate appeared first on Smithsonian Insider.

The post Creating a dictionary: Gabriela Pérez Báez, Curator of Linguistics appeared first on Smithsonian Insider.

What is it like to be the curator of Great Cats at the National Zoo? We interviewed Craig Saffoe to hear firsthand.

The post What is it like to be curator of Great Cats at the National Zoo? 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, […]

The post Studying migratory connectivity of shorebirds on the Texas coast appeared first on Smithsonian Insider.

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.

Click here to read more about the work of the Laser Interferometer Gravitational-Wave Observatory. The Smithsonian has been celebrating innovation in American culture for more than […]

The post Stephen Hawking Congratulates LIGO Team on its Smithsonian American Ingenuity Award appeared first on Smithsonian Insider.

Ohkay Owingeh from Adventure Pictures on Vimeo. Currently featured in the exhibition “By the People” at the Cooper Hewitt, Smithsonian Design Museum in New York City […]

The post Restoration of the Ohkay Owingeh Tribe’s historic pueblo appeared first on Smithsonian Insider.

Time-lapse captured at the Hirshhorn Museum of Yayoi Kusama’s The Obliteration Room, on view in “Yayoi Kusama: Infinity Mirrors.” In Yayoi Kusama’s “The Obliteration Room,” […]

The post Adding 750,000 dots to The Obliteration Room appeared first on Smithsonian Insider.

Timelapse video of Flight operations aboard the USS Dwight D. Eisenhower brought to you by the Smithsonian’s National Air and Space Museum.

The post Flight Operations on the USS Eisenhower appeared first on Smithsonian Insider.

On World Elephant Day–Saturday, Aug. 12, 2017–the Smithsonian’s National Zoo celebrated Ambika the elephant’s 70th birthday. Hear her keepers of more than 30 years talk […]

The post Celebrating Ambika’s 56 years at National Zoo appeared first on Smithsonian Insider.

Tuvan ensemble Alash demonstrates various traditional throat singing styles that they use in their music. Smithsonian Folkways Recordings video.

The post Alash demonstrates throat singing styles appeared first on Smithsonian Insider.

Lodgepole pine drawn in 1898 by U.S. National Herbarium illustrator Frederick Andrew Walpole.

The post Frederick Walpole illustrations recovered appeared first on Smithsonian Insider.

The North Pole isn’t the only place on Earth affected by slight increases in temperature. Until recently, scientific thinking used to posit that tropical forests, […]

The post Rising temperatures mean more blooms for tropical rainforests appeared first on Smithsonian Insider.

As mangrove trees lose ground to deforestation and urban sprawl, one development seems to be giving them a boost: climate change. Fewer winter cold snaps […]

The post Mangroves creep north in response to warmer temperatures appeared first on Smithsonian Insider.

How more than 1,000 tree species may occur in a small area of forest in Amazonia or Borneo is an unsolved mystery. Their ability to […]

The post Trees employ similar strategies to outcompete their neighbors appeared first on Smithsonian Insider.

The Smithsonian Tropical Research Institute (STRI) celebrated with Panama the completion of the Panama Canal expansion project on June 26, 2016. The $5.6 billion engineering […]

The post Smithsonian celebrates Panama Canal expansion! appeared first on Smithsonian Insider.

Millions, if not billions, of specimens reside in the world’s natural history collections, but most of these have not been carefully studied, or even looked […]

The post Using digitized Botany specimens, AI excels in simple curatorial tasks appeared first on Smithsonian Insider.

The structural and nonlinear optical properties of a new anilinium hybrid crystal of chemical formula (C6H7NCl+·NO3−)3 have been investigated. The crystal structure was determined from single-crystal X-ray diffraction measurements performed at a temperature of 100 K which show that the compound crystallizes in a noncentrosymmetric space group (Pna21). The structural analysis was coupled with Hirshfeld surface analysis to evaluate the contribution of the different intermolecular interactions to the formation of supramolecular assemblies in the solid state that exhibit nonlinear optical features. This analysis reveals that the studied compound is characterized by a three-dimensional network of hydrogen bonds and the main contributions are provided by the O...H, C...H, H...H and Cl...H interactions, which alone represent ∼85% of the total contributions to the Hirshfeld surfaces. It is noteworthy that the halogen...H contributions are quite comparable with those of the H...H contacts. The nonlinear optical properties were investigated by nonlinear diffuse femtosecond-pulse reflectometry and the obtained results were compared with those of the reference material LiNbO3. The hybrid crystals exhibit notable second (SHG) and third (THG) harmonic generation which confirms its polarity is generated by the different intermolecular interactions. These measurements also highlight that the THG signal of the new anilinium compound normalized to its SHG counterpart is more pronounced than for LiNbO3.

Simulink might produce an incorrect sorted order for a model that meets all of the following conditions:

• The model contains blocks from the SoC Blockset
• The Signal logging option is selected in the model configuration set
• Signals using asynchronous sample time are configured for logging

When the Signal Editor is saving data, the indicator that the save is occurring does not appear.  You might notice a delay when saving large data files.This bug exists in the following release(s):
R2020a

Interested in Upgrading?

The title com­pound, tetra­ethyl­ammonium tetra­thio­rhenate, [(C2H5)4N][ReS4], has, at room temperature, a disordered structure in the space group P63mc (Z = 2, α-phase). A phase transition to the monoclinic space group P21 (Z = 2, γ-phase) at 285 K leads to a pseudo-merohedral twin. The high deviation from the hexa­gonal metric causes split reflections. However, the different orientations could not be separated, but were integrated using a large integration box. Rapid cooling to 110–170 K produces a metastable β-phase (P63, Z = 18) in addition to the γ-phase. All crystals of the β-phase are contaminated with the γ-phase. Additionally, the crystals of the β-phase are merohedrally twinned. In contrast to the α-phase, the β- and γ-phases do not show disorder.