Fond of a range of marine and freshwater vegetation such as turtle grass and eelgrass, the Florida manatee spends most of its waking hours grazing […]

The post Algae bloom toxins may make Florida’s manatees and sea turtles susceptible to deadly accidents appeared first on Smithsonian Insider.

Astronomers are constantly on the hunt for ever-colder star-like bodies, and two years ago a new class of objects was discovered by researchers using NASA’s […]

The post Coldest brown dwarfs blur lines between stars and planets appeared first on Smithsonian Insider.

Sometime during the Middle Eocene a prehistoric mosquito slurped down a final blood meal then died and sank to the bottom of a pond in […]

The post Blood molecules preserved for millions of years in abdomen of fossil mosquito appeared first on Smithsonian Insider.

It is one of the most sensitive noses in the animal kingdom but what its owner seeks is no pungent bed of roses, in fact […]

The post Study shows turkey vulture is doubly blessed with acute vision and sense of smell appeared first on Smithsonian Insider.

Scientists from the Smithsonian’s National Museum of Natural History have just named and described the Spectacular Guyane False-form beetle, or Guyanemorpha spectabilis, from Guyane (French Guiana). […]

The post Remarkably large and colorful new beetle discovered in French Guiana appeared first on Smithsonian Insider.

It has all the hallmarks of a paleontological crime scene: a massive graveyard along a remote desert highway containing the fossil bones of at least […]

The post Algae assassin found responsible for whale mass grave in Chile appeared first on Smithsonian Insider.

A newly released study focusing on an extinct species, the Caribbean monk seal (Monachus tropicalis), has revealed just how evolutionarily unique its only two living […]

The post Too valuable to lose: Extinct relative reveals rarity of last two remaining monk seal species appeared first on Smithsonian Insider.

The practice of selectively fishing male blue crabs in the Chesapeake—intended to give females a chance to reproduce—may have a hidden cost. A Bay without […]

The post With too few males, blue crab population may be put at risk appeared first on Smithsonian Insider.

The report card is in for the state of the birds in the USA. So how did we do? Certainly not an A+ or even […]

The post Our birds are in real trouble. Can we fix it? Yes we can! appeared first on Smithsonian Insider.

The rusty-patched bumble bee (Bombus affinis), which has not been seen in the eastern United States in five years, has been found by a Smithsonian […]

The post Rare rusty-patched bumble bee discovered in Virginia survey appeared first on Smithsonian Insider.

Unless you live under a lunar rock, you’ve probably heard about or seen director Christopher Nolan’s latest blockbuster “Interstellar.” Starring Anne Hathaway and Matthew McConaughey, […]

The post Interstellar exploration – five planets where humans may (or may not) be able to live someday appeared first on Smithsonian Insider.

A new study by Florida State University and Smithsonian Institution biologists shows that bleaching events brought on by rising sea temperatures are having a detrimental […]

The post Study: Bleaching events impair long-term coral reproduction appeared first on Smithsonian Insider.

A new study of microorganisms living on the skin and in the intestines of North America vultures (black and turkey vultures) has turned up a […]

The post Vultures remarkably tolerant to deadly bacteria, study reveals appeared first on Smithsonian Insider.

Eaten raw and thinly sliced, the dark-red belly meat of the Pacific bluefin tuna is highly prized—and priced—for its rich oily flavor by sashimi and […]

The post Desire for Pacific bluefin puts fish on red list of threatened species appeared first on Smithsonian Insider.

Every massive galaxy has a black hole at its center, and the heftier the galaxy, the bigger its black hole. But why are the two […]

The post Dark matter guides growth of supermassive black holes appeared first on Smithsonian Insider.

Giant pandas. Grizzlies. Polar bears. You’ve probably heard a lot about these bear species, but what about Andean bears? To the Quechua and Aymara, the […]

The post 6 Things You Probably Didn’t Know About Andean Bears appeared first on Smithsonian Insider.

“Early Women in Science” is an online exhibition of 16 women scientists who began their work before 1922. A Biodiversity Heritage Library exhibition, it profiles forward-thinking […]

The post “Early Women in Science” Profiles Trailblazing Women appeared first on Smithsonian Insider.

Researchers have discovered a black hole that grew much more quickly than its host galaxy. The discovery calls into question previous assumptions on the development […]

The post A Precocious Black Hole appeared first on Smithsonian Insider.

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 […]

The post Digitized, Searchable Archives Help Revive ‘Sleeping’ Languages appeared first on Smithsonian Insider.

Tiny Anolis lizards preserved since the Miocene in amber are giving scientists a true appreciation of the meaning of community stability. Dating back some 15 […]

The post Trapped in Amber: Ancient fossils reveal remarkable stability of Caribbean lizard communities appeared first on Smithsonian Insider.

Most people think of black holes as giant vacuum cleaners sucking in everything that gets too close. But the supermassive black holes at the centers […]

The post Event Horizon Telescope Reveals Magnetic Fields at Milky Way’s Central Black Hole appeared first on Smithsonian Insider.

In April 2015, after traveling for about half the age of the universe, a flood of powerful gamma rays from a distant galaxy slammed into […]

The post VERITAS Detects Gamma Rays from Galaxy Halfway Across the Visible Universe appeared first on Smithsonian Insider.

New fossils found in Northeastern China have revealed a remarkable evolutionary coincidence: an extinct group of insects known as Kalligrammatid lacewings (Order Neuroptera) share an […]

The post Remarkable butterfly look-alike lived 50 million years before butterflies appeared appeared first on Smithsonian Insider.

Einstein’s general theory of relativity predicts the emission of gravitational waves by massive celestial bodies moving though space-time. For the past century gravitational waves have […]

The post Astronomers complete First Search for Visible Light Associated with Gravitational Waves appeared first on Smithsonian Insider.

On September 14, 2015, the Laser Interferometer Gravitational-wave Observatory (LIGO) detected gravitational waves from the merger of two black holes 29 and 36 times the […]

The post Ligo’s Twin Black Holes Might Have Been Born Inside a Single Star appeared first on Smithsonian Insider.

The results are in, 2016 is going to be a good year for blue crabs in the Chesapeake Bay. An iconic figure embedded in the […]

The post Smithsonian Expert Urges Caution, Patience on Blue Crab Recovery appeared first on Smithsonian Insider.

When is a blue bird not blue? The answer to this question is always. There actually is no such thing as a blue bird. To find […]

The post When Is a Blue Bird Not Blue? appeared first on Smithsonian Insider.

The center of the Milky Way galaxy is currently a quiet place where a supermassive black hole slumbers, only occasionally slurping small sips of hydrogen […]

The post The Milky Way’s blowout bash 6 million years ago! appeared first on Smithsonian Insider.

Every few thousand years, an unlucky star wanders too close to the black hole at the center of the Milky Way. The black hole’s powerful […]

The post Our Galaxy’s Black Hole is Spewing Planet-size “Spitballs” appeared first on Smithsonian Insider.

Food is scarce in the deep, dark regions of the ocean where barbeled dragonfishes and their relatives dwell. Known as the Stomiidae, some of these […]

The post Odd anatomy: flexible joint between skull and spine allow dragonfish to open wide appeared first on Smithsonian Insider.

To fully know a species and develop sound conservation efforts, its full life cycle must be understood. But tracking small migratory birds for thousands of […]

The post Keeping Track of Kirtland’s Warbler All Year Long―A Scientific First appeared first on Smithsonian Insider.

AUSTIN, Texas — Astronomers at The University of Texas at Austin and Harvard University have put a basic principle of black holes to the test, […]

The post Do Stars Fall Quietly into Black Holes? appeared first on Smithsonian Insider.

Sometimes there’s just no telling what will turn up at the local market. Fish biologist Jeff Williams of the Smithsonian’s National Museum of Natural History […]

The post Surprise: Distinctive new surgeonfish species makes an improbable debut appeared first on Smithsonian Insider.

Two separate teams of scientists have identified major challenges for the development of life in what has recently become one of the most famous exoplanet […]

The post There’s more to extraterrestrial life than planets in “habitable zone” orbits appeared first on Smithsonian Insider.

Covered in sharp spines, when harassed the porcupine fish inflates like a balloon. Think of a small soccer ball bristling all over with nails. Most predators […]

The post Indestructible jaws from ancient, extinct porcupine fish reveal new species appeared first on Smithsonian Insider.

The center of our Galaxy has been intensely studied for many years, but it still harbors surprises for scientists. A snake-like structure lurking near our […]

The post Cosmic filament probes our galaxy’s giant black hole appeared first on Smithsonian Insider.

A team of astrophysicists and planetary scientists has predicted that Neptune-like planets located near the center of the Milky Way galaxy have been transformed into […]

The post Black hole blasts may transform “Mini-Neptunes” into rocky worlds appeared first on Smithsonian Insider.

When the heat and humidity of the Washington, D.C. summer sends its residents scrambling for air conditioning and iced coffee, the animal care specialists at […]

The post How do National Zoo animals beat the heat? Bloodsicles and other frozen delicacies appeared first on Smithsonian Insider.

This user-friendly, portable, and extensive identification guide features large color illustrations of more than 900 species; the first range maps published to show the distribution of Panama's birds and concise text that describes field marks for identification, as well as habitat, behavior, and vocalizations.

The post Smithsonian ornithologist publishes new guide to the birds of Panama 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.

Yinlong Song, Yikan Zhang, Ying Pan, Jianfeng He, Yan Wang, Wei Chen, Jing Guo, Haiteng Deng, Yi Xue, Xianyang Fang, and Xin Liang

Microtubules dynamics is regulated by the plus end-tracking proteins (+TIPs) in cells. End binding protein 1 (EB1) acts as a master regulator in +TIPs networks by targeting microtubule growing ends and recruiting other factors. However, the molecular mechanism of how EB1 binds to microtubule ends with a high affinity remains to be an open question. Using single-molecule imaging, we show that the end-binding kinetics of EB1 changes along with the polymerizing and hydrolysis rate of tubulin dimers, confirming the binding of EB1 to GTP/GDP-Pi tubulin at microtubule growing ends. The affinity of wild-type EB1 to these sites is higher than monomeric EB1 mutants, suggesting that two CH domains in the dimer contribute to the end-binding. Introducing phosphomimicking mutations into the linker domain of EB1 weakens the end-binding affinity and confers a more curved conformation to EB1 dimer without compromising dimerization, suggesting that the overall architecture of EB1 is important for the end-binding affinity. Taken together, our results provide insights into understanding how the high-affinity end-binding of EB1 can be achieved and how this activity may be regulated in cells.

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.

Xian Hu, Salma Jalal, Michael Sheetz, Oddmund Bakke, and Felix Margadant

Despite progress made in confocal microscopy, even fast systems still have insufficient temporal resolution for detailed live cell volume imaging, such as tracking rapid movement of membrane vesicles in three-dimensional space. Depending on the shortfall, this may result in undersampling and/or motion artifacts that ultimately limit the quality of the imaging data. By sacrificing detailed information in the Z-direction, we propose a new imaging modality that involves capturing fast "projections" from the field of depth which shortens imaging time by approximately an order of magnitude as compared to standard volumetric confocal imaging. With faster imaging, radiation exposure to the sample is reduced, resulting in less fluorophore photobleaching and potential photodamage. The implementation minimally requires two synchronized control signals that drive a piezo stage and trigger the camera exposure. The device generating the signals has been tested on spinning disk confocals and instant structured-illumination-microscopy (iSIM) microscopes. Our calibration images show that the approach provides highly repeatable and stable imaging conditions that enable photometric measurements of the acquired data, in both standard live imaging and super-resolution modes.

Kasun Buddika, Ishara S. Ariyapala, Mary A. Hazuga, Derek Riffert, and Nicholas S. Sokol

Stressed cells downregulate translation initiation and assemble membrane-less foci termed stress granules (SGs). Extensively characterized in cultured cells, the existence of such structures in stressed adult stem cell pools remain poorly characterized. Here we report that Drosophila orthologs of mammalian SG components AGO1, ATX2, CAPRIN, eIF4E, FMRP, G3BP, LIN-28, PABP, and TIAR are enriched in adult intestinal progenitor cells where they accumulate in small cytoplasmic messenger ribonucleoprotein complexes (mRNPs). Treatment with sodium arsenite or rapamycin reorganized these mRNPs into large cytoplasmic granules. Formation of these intestinal progenitor stress granules (IPSGs) depended on polysome disassembly, led to translational downregulation, and was reversible. While canonical SG nucleators ATX2 and G3BP were sufficient for IPSG formation in the absence of stress, neither of them, nor TIAR, either individually or collectively, were required for stress-induced IPSG formation. This work therefore finds that IPSGs do not assemble via a canonical mechanism, raising the possibility that other stem cell populations employ a similar stress-response mechanism.

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.

Laurence Haren, Dorian Farache, Laurent Emorine, and Andreas Merdes

-tubulin is a major protein involved in the nucleation of microtubules in all eukaryotes. It forms two different complexes with proteins of the GCP family (gamma-tubulin complex proteins): -tubulin small complexes (TuSCs), containing -tubulin and GCPs 2 and 3, and -tubulin ring complexes (TuRCs), containing multiple TuSCs, in addition to GCPs 4, 5, and 6. Whereas the structure and assembly properties of TuSCs have been intensively studied, little is known about the assembly of TuRCs, and about the specific roles of GCPs 4, 5, and 6. Here, we demonstrate that two copies of GCP4 and one copy each of GCP5 and GCP6 form a salt-resistant sub-complex within the TuRC that assembles independently of the presence of TuSCs. Incubation of this sub-complex with cytoplasmic extracts containing TuSCs leads to the reconstitution of TuRCs that are competent to nucleate microtubules. In addition, we investigate sequence extensions and insertions that are specifically found at the amino-terminus of GCP6, and between the GCP6 grip1 and grip2 motifs, and we demonstrate that these are involved in the assembly or stabilization of the TuRC.

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.