In this fun, accessible and informative book, ichthyologists Gene Helfman, professor emeritus at the University of Georgia, and Bruce Collette, of the Division of Fishes at the Smithsonian’s National Museum of Natural History, provide accurate, entertaining, and sometimes surprising answers to more than 100 common and not-so-common questions.

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When it comes to the birds of South Asia, Pamela Rasmussen wrote the book on it. Literally. Twice.

The post New Book: “Birds of South Asia: The Ripley Guide” appeared first on Smithsonian Insider.

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.

David Guerit, Pauline Marie, Anne Morel, Justine Maurin, Christel Verollet, Brigitte Raynaud-Messina, Serge Urbach, and Anne Blangy

Among hematopoietic cells, osteoclasts (Oc) and immature dendritic cells (Dc) are closely related myeloid cells with distinct functions; Oc participate skeleton maintenance while Dc sample the environment for foreign antigens. Such specificities rely on profound modifications of gene and protein expression during Oc and Dc differentiation. We provide global proteomic and transcriptomic analyses of primary mouse Oc and Dc, based on original SILAC and RNAseq data. We established specific signatures for Oc and Dc including genes and proteins of unknown functions. In particular, we showed that Oc and Dc have the same α and β tubulin isotypes repertoire but that Oc express much more β tubulin isotype Tubb6. In both mouse and human Oc, we demonstrate that elevated expression of Tubb6 in Oc is necessary for correct podosomes organization and thus for the structure of the sealing zone, which sustains the bone resorption apparatus. Hence, lowering Tubb6 expression hindered Oc resorption activity. Overall, we highlight here potential new regulators of Oc and Dc biology and illustrate the functional importance of the tubulin isotype repertoire in the biology of differentiated cells.

Kristina Drizyte-Miller, Jing Chen, Hong Cao, Micah B. Schott, and Mark A. McNiven

Epithelial cells such as liver-resident hepatocytes rely heavily on the Rab family of small GTPases to perform membrane trafficking events that dictate cell physiology and metabolism. Not surprisingly, disruption of several Rabs can manifest in metabolic diseases or cancer. Rab32 is expressed in many secretory epithelial cells but its role in cellular metabolism is virtually unknown. In this study, we find that Rab32 associates with lysosomes and regulates proliferation and cell size of Hep3B hepatoma and HeLa cells. Specifically, we identify that Rab32 supports mTORC1 signaling under basal and amino acid stimulated conditions. Consistent with inhibited mTORC1, an increase in nuclear TFEB localization and lysosome biogenesis is also observed in Rab32-depleted cells. Finally, we find that Rab32 interacts with mTOR kinase and that loss of Rab32 reduces the association of mTOR and mTORC1 pathway proteins with lysosomes, suggesting that Rab32 regulates lysosomal mTOR trafficking. In summary, these findings suggest that Rab32 functions as a novel regulator of cellular metabolism through supporting mTORC1 signaling.

Victor J. F. Kitano, Yoko Ohyama, Chiyomi Hayashida, Junta Ito, Mari Okayasu, Takuya Sato, Toru Ogasawara, Maki Tsujita, Akemi Kakino, Jun Shimada, Tatsuya Sawamura, and Yoshiyuki Hakeda

Osteoporosis is associated with vessel diseases attributed to hyperlipidemia, and bone resorption by multinucleated osteoclasts is related to lipid metabolism. In this study, we generated low-density lipoprotein receptor (LDLR)/lectin-like oxidized LDL receptor-1 (LOX-1) double knockout (dKO) mice. We found that, like LDLR single KO (sKO), LDLR/LOX-1 dKO impaired cell-cell fusion of osteoclast-like cells (OCLs). LDLR/LOX-1 dKO and LDLR sKO preosteoclasts exhibited decreased uptake of LDL. The cell surface cholesterol levels of both LDLR/LOX-1 dKO and LDLR sKO osteoclasts were lower than the levels of wild-type OCLs. Additionally, the amount of phosphatidylethanolamine (PE) on the cell surface was attenuated in LDLR/LOX-1 dKO and LDLR sKO pre-OCLs, while the PE distribution in wild-type OCLs was concentrated on the filopodia in contact with neighboring cells. Abrogation of the ATP binding cassette G1 (ABCG1) transporter, which transfers PE to the cell surface, caused decreased PE translocation to the cell surface and subsequent cell-cell fusion. The findings of this study indicate the involvement of a novel cascade (LDLR~ABCG1~PE translocation to cell surface~cell-cell fusion) in multinucleation of OCLs.

Su Ming Sun, Amandine Batte, Mireille Tittel-Elmer, Sophie van der Horst, Tibor van Welsem, Gordon Bean, Trey Ideker, Fred van Leeuwen, and Haico van Attikum

Eukaryotic chromosomes are replicated in interphase and the two newly duplicated sister chromatids are held together by the cohesin complex and several cohesin auxiliary factors. Sister chromatid cohesion is essential for accurate chromosome segregation during mitosis, yet has also been implicated in other processes, including DNA damage repair, transcription and DNA replication. To assess how cohesin and associated factors functionally interconnect and coordinate with other cellular processes, we systematically mapped genetic interactions of 17 cohesin genes centered on quantitative growth measurements of >52,000 gene pairs in budding yeast. Integration of synthetic genetic interactions unveiled a cohesin functional map that constitutes 373 genetic interactions, revealing novel functional connections with post-replication repair, microtubule organization and protein folding. Accordingly, we show that the microtubule-associated protein Irc15 and the prefoldin complex members Gim3, Gim4 and Yke2 are new factors involved in sister chromatid cohesion. Our genetic interaction map thus provides a unique resource for further identification and functional interrogation of cohesin proteins. Since mutations in cohesin proteins have been associated with cohesinopathies and cancer, it may also identify cohesin interactions relevant in disease etiology.

Juan Martin D'Ambrosio, Veronique Albanese, Nicolas-Frederic Lipp, Lucile Fleuriot, Delphine Debayle, Guillaume Drin, and Alenka Copic

Osh6 and Osh7 are lipid transfer proteins (LTPs) that move phosphatidylserine (PS) from the endoplasmic reticulum (ER) to the plasma membrane (PM). High PS level at the PM is key for many cellular functions. Intriguingly, Osh6/7 localize to ER-PM contact sites, although they lack membrane-targeting motifs, in contrast to multidomain LTPs that both bridge membranes and convey lipids. We show that Osh6 localization to contact sites depends on its interaction with the cytosolic tail of the ER-PM tether Ist2, a homologue of TMEM16 proteins. We identify a motif in the Ist2 tail, conserved in yeasts, as the Osh6-binding region, and we map an Ist2-binding surface on Osh6. Mutations in the Ist2 tail phenocopy osh6 osh7 deletion: they decrease cellular PS levels, and block PS transport to the PM. Our study unveils an unexpected partnership between a TMEM16-like protein and a soluble LTP, which together mediate lipid transport at contact sites.

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.

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.

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.

We value gold for many reasons: its beauty, its usefulness as jewelry, and its rarity. Gold is rare on Earth in part because it’s also […]

The post Earth’s gold came from colliding dead stars appeared first on Smithsonian Insider.

Everyone knows that the gravitational tugging of the moon makes earth’s oceans swell and recede. But did you know Earth’s tugging is causing the moon […]

The post Shrinking Moon Linked to Earth’s Tidal Forces appeared first on Smithsonian Insider.

Looking for another Earth? An international team of researchers has pinpointed which of the more than 4,000 exoplanets discovered by NASA’s Kepler mission are most […]

The post Another Earth? Kepler astronomers pinpoint likeliest candidates appeared first on Smithsonian Insider.

At 7:05 pm (EDT), Thursday, Sept. 8, NASA plans to launch a spacecraft to a near-Earth asteroid named Bennu. Among that spacecraft’s five instruments is […]

The post Asteroid Mission carries Student X-ray Experiment appeared first on Smithsonian Insider.

Cambridge, MA -Physicists are capitalizing on a direct connection between the largest cosmic structures and the smallest known objects to use the universe as a […]

The post Scientists are using the universe as a “cosmological collider” appeared first on Smithsonian Insider.

Crystal structure identification of thin organic films entails a number of technical and methodological challenges. In particular, if molecular crystals are epitaxially grown on single-crystalline substrates a complex scenario of multiple preferred orientations of the adsorbate, several symmetry-related in-plane alignments and the occurrence of unknown polymorphs is frequently observed. In theory, the parameters of the reduced unit cell and its orientation can simply be obtained from the matrix of three linearly independent reciprocal-space vectors. However, if the sample exhibits unit cells in various orientations and/or with different lattice parameters, it is necessary to assign all experimentally obtained reflections to their associated individual origin. In the present work, an effective algorithm is described to accomplish this task in order to determine the unit-cell parameters of complex systems comprising different orientations and polymorphs. This method is applied to a polycrystalline thin film of the conjugated organic material 6,13-pentacene­quinone (PQ) epitaxially grown on an Ag(111) surface. All reciprocal vectors can be allocated to unit cells of the same lattice constants but grown in various orientations [sixfold rotational symmetry for the contact planes (102) and (102)]. The as-determined unit cell is identical to that reported in a previous study determined for a fibre-textured PQ film. Preliminary results further indicate that the algorithm is especially effective in analysing epitaxially grown crystallites not only for various orientations, but also if different polymorphs are present in the film.

The generalized Darwin–Hamilton equations [Wuttke (2014). Acta Cryst. A70, 429–440] describe multiple Bragg reflection from a thick, ideally imperfect crystal. These equations are simplified by making full use of energy conservation, and it is demonstrated that the conventional two-ray Darwin–Hamilton equations are obtained as a first-order approximation. Then an efficient numeric solution method is presented, based on a transfer matrix for discretized directional distribution functions and on spectral collocation in the depth coordinate. Example solutions illustrate the orientational spread of multiply reflected rays and the distortion of rocking curves, especially if the detector only covers a finite solid angle.

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.

The post Smithsonian biologist Rachel Collin visits the Universidad Austral de Chile to collect special snails for her research. appeared first on Smithsonian Insider.

The post Salamanders: The Hidden Jewels of Appalachia appeared first on Smithsonian Insider.

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.

The post Kari Bruwelheide, forensic anthropologist at the Smithsonian’s National Museum of Natural History, discusses the power of bones. appeared first on Smithsonian Insider.

Jonathan Coddington, Curator of Spiders at the Smithsonian National Museum of Natural History describes how photography has transformed the study of arachnids.

The post How photography has transformed the study of spiders and their webs 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 Short video featuring the fieldwork of Smithsonian scientists created in 2000, posted by the Smithsonian Archives appeared first on Smithsonian Insider.

This scientific visualization is much more than a dizzying dance of whirling worlds. It shows 2,299 planets found by NASA’s Kepler planet-hunting spacecraft.

The post Animation: Dizzying dance of the Kepler candidates 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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Bocas Research Station’s research assistant Arcadio Castillo ran into these curious looking fish babies while working close to the dock. After some investigation, we found […]

The post Toadfish (Batrachoididae) babies in Bocas del Toro, Panama appeared first on Smithsonian Insider.

Maintaining natural movement of animals that live in the tropical rainforest canopy in South America is important for the health of the ecosystem. As development […]

The post Tremie Gregory uses camera traps to study “bridges” in the rainforest canopy appeared first on Smithsonian Insider.

Get a look behind the scenes as we installed “Outside the Spacecraft: 50 Years of Extra-vehicular Activity,” a new exhibition on view at the Museum […]

The post “Outside the Spacecraft,” a new exhibition at the Air and Space Museum 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.

Arachnophobes fearful of spiders jumping, creeping or falling into their beds now have something new to worry about. Some spiders might also glide in through the window. […]

The post Scientists study Skydiving spiders in South America appeared first on Smithsonian Insider.

Jessica Lunt, Postdoctoral Fellow at the Smithsonian Marine Station in Fort Pierce, Fla., shows how her oyster sampling fieldwork looks at what lives on these […]

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No divers were in danger when two large squid (species Taningia danae) began acting aggressively toward a robot submersible operated deep in the Pacific from NOAA’s […]

The post Rare squid “T. danae” captured in new video appeared first on Smithsonian Insider.

Just like humans, great apes can catch the flu. That’s why the Smithsonian’s National Zoo’s primate keepers train our gorillas and orangutans—like Iris, featured here—to […]

The post Get a flu shot? These orangutans did…. appeared first on Smithsonian Insider.

Sponsored by the Smithsonian Asian Pacific American Center and created by filmmaker Frank Chi, this short film features letters that young Japanese Americans in World […]

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This video highlights the mass-digitization of the National Postal Museum’s Sidney N. Shure Collection of Israeli and Palestinian stamps and covers.

The post National Postal Museum Rapid Capture Project appeared first on Smithsonian Insider.

Last October Smithsonian Folkways released “The Brothers Nazaroff: The Happy Prince,” a boisterous, high-energy tribute to cult Yiddish troubadour Nathan “Prince” Nazaroff, who recorded the […]

The post Animated Music Video: “Ich A Mazeldicker Yid” by The Brothers Nazaroff appeared first on Smithsonian Insider.

The post Smithsonian Secretary David Skorton on why he votes appeared first on Smithsonian Insider.

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Happy Holidays from the Smithsonian’s National Air and Space Museum!

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Known around the world for personal and culturally inspired choreography, Dana Tai Soon Burgess has been named the Smithsonian’s first choreographer-in-residence at the National Portrait […]

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