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.

Samantha-Su Z. Taylor, Nicole L. Jacobsen, Tasha K. Pontifex, Paul Langlais, and Janis M. Burt

Connexin 37 (Cx37) expression profoundly suppresses proliferation of rat insulinoma (Rin) cells in a manner dependent on gap junction channel (GJCh) functionality and the presence and phosphorylation status of its carboxyl-terminus (CT). In Rin cells growth arrested by induced Cx37 expression, serine 319 (S319) is frequently phosphorylated. Preventing phosphorylation at this site (alanine substitution; S319A) relieved Cx37 of its growth suppressive effect whereas mimicking phosphorylation at this site (aspartate substitution; S319D) enhanced Cx37's growth suppressive properties. Like Cx37-WT, -S319D GJChs and hemichannels (HChs) preferred the closed state, rarely opening fully, and gated slowly. In contrast, Cx37-S319A channels preferred open states, opened fully, and gated rapidly. These data indicate that phosphorylation-dependent conformational differences in Cx37 protein and channel function underlie Cx37-induced growth arrest vs. growth permissive phenotypes. That the closed state of -WT and Cx37-S319D GJChs and HChs favors growth arrest suggests that rather than specific permeants mediating cell cycle arrest, the closed conformation instead supports interaction of Cx37 with growth regulatory proteins that result in growth arrest.

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.

The Smithsonian’s National Museum of Natural History recently acquired four remarkable gemstones and jewelry pieces for the Smithsonian’s National Gem Collection in celebration of the 100th anniversary of the museum.

The post National Museum of Natural History acquires gemstones in honor of its 100th anniversary appeared first on Smithsonian Insider.

Formed some 250,000 years ago when the Nile River pushed through a low channel near Wadi Tushka, it flooded the eastern Sahara, creating a lake that at its highest level covered more than 42,000 square miles.

The post Ancient megalake discovered beneath Sahara Desert appeared first on Smithsonian Insider.

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.

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.

The post The Forgotten Dinosaur Hunter appeared first on Smithsonian Insider.

Have an upset stomach? Pop a chalky, chewable antacid. Maybe you’ve got a painful cut or burn. No problem; reach for a healing ointment or […]

The post Glittering, mesmerizing, lifesaving: Hospital exhibit showcases minerals used in medicine appeared first on Smithsonian Insider.

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 […]

The post NASA, Smithsonian renew hunt for Antarctic meteorites appeared first on Smithsonian Insider.

Several weeks before it went on display in mid-November at the Smithsonian’s National Museum of Natural History, minerals curator Jeff Post stood in the museum’s […]

The post Colossal diamond’s eerie glow earns it a fiery name appeared first on Smithsonian Insider.

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 […]

The post Microplastics in our environment: A conversation with Odile Madden, Smithsonian plastics scientist appeared first on Smithsonian Insider.

To get a better idea of just what is going on with the current volcanic eruption of Kilauea on the island of Hawaii, take a […]

The post Kilauea’s activity is nothing new, says a Smithsonian volcano expert appeared first on Smithsonian Insider.

A crystallographic indexing algorithm, pinkIndexer, is presented for the analysis of snapshot diffraction patterns. It can be used in a variety of contexts including measurements made with a monochromatic radiation source, a polychromatic source or with radiation of very short wavelength. As such, the algorithm is particularly suited to automated data processing for two emerging measurement techniques for macromolecular structure determination: serial pink-beam X-ray crystallography and serial electron crystallography, which until now lacked reliable programs for analyzing many individual diffraction patterns from crystals of uncorrelated orientation. The algorithm requires approximate knowledge of the unit-cell parameters of the crystal, but not the wavelengths associated with each Bragg spot. The use of pinkIndexer is demonstrated by obtaining 1005 lattices from a published pink-beam serial crystallography data set that had previously yielded 140 indexed lattices. Additionally, in tests on experimental serial crystallography diffraction data recorded with quasi-monochromatic X-rays and with electrons the algorithm indexed more patterns than other programs tested.

In this study, the atomic structure of the ternary icosahedral ZnMgTm quasicrystal (QC) is investigated by means of single-crystal X-ray diffraction. The structure is found to be a member of the Bergman QC family, frequently found in Zn–Mg–rare-earth systems. The ab initio structure solution was obtained by the use of the Superflip software. The infinite structure model was founded on the atomic decoration of two golden rhombohedra, with an edge length of 21.7 Å, constituting the Ammann–Kramer–Neri tiling. The refined structure converged well with the experimental diffraction diagram, with the crystallographic R factor equal to 9.8%. The Bergman clusters were found to be bonded by four possible linkages. Only two linkages, b and c, are detected in approximant crystals and are employed to model the icosahedral QCs in the cluster approach known for the CdYb Tsai-type QC. Additional short b and a linkages are found in this study. Short interatomic distances are not generated by those linkages due to the systematic absence of atoms and the formation of split atomic positions. The presence of four linkages allows the structure to be pictured as a complete covering by rhombic triacontahedral clusters and consequently there is no need to define the interstitial part of the structure (i.e. that outside the cluster). The 6D embedding of the solved structure is discussed for the final verification of the model.

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.

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

The post “How Soil Savvy are You?, is featured in the exhibition “Dig It! The Secrets of Soil,” from the Smithsonian Traveling Exhibition Service 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.

The post Salamanders: The Hidden Jewels of Appalachia 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 The amazing story of adaptation and survival in our species, Homo sapiens. appeared first on Smithsonian Insider.

The post Samuel P. Langley, Secretary of the Smithsonian, and his development of the ill-fated Aerodrome A appeared first on Smithsonian Insider.

The Smithsonian Tropical Research Institute

The post Join the longest conversation in tropical biology appeared first on Smithsonian Insider.

The National Museum of Natural History in Washington, D.C., has closed its Dinosaur Hall for a five-year renovation. But before the overhaul can begin, the […]

The post How do you dismantle a dinosaur? appeared first on Smithsonian Insider.

The moon passed between the Earth and the sun on Thursday, Oct. 23. While avid stargazers in North America looked up to watch the spectacle, the […]

The post Polar-orbiting satellite captures amazing X-ray footage of solar eclipse appeared first on Smithsonian Insider.

NASA’s Kepler mission is responsible for history’s first detection of Earth-sized planets orbiting other suns in their temperate “habitable zones.” The team in charge of […]

The post NASA’s Kepler mission receives National Air and Space Museum’s highest group honor appeared first on Smithsonian Insider.

How do you bring a nearly complete T. rex back to life? You send the fossils to Canada where craftsmen create a creature of steel. […]

The post First Look: The Smithsonian builds a dinosaur appeared first on Smithsonian Insider.

U.S. Secretary of the Interior Sally Jewell talks about the importance of bird conservation and why birds really matter. Step outside your house in the […]

The post Why Birds Really Matter: Sally Jewell appeared first on Smithsonian Insider.

The post Smithsonian Secretary David Skorton on USA Today TV appeared first on Smithsonian Insider.

Amateur paleontologist, Ray Stanford, describes his experience of discovering the impression of a dinosaur and determining that it was a new species. This video is […]

The post What is it like to discover a new dinosaur? appeared first on Smithsonian Insider.

As the host of PBS’s “Scientific American Frontiers,” Alan Alda has interviewed scientists, physicists, neuroscientists, and academics. Forging a connection with these guests through freewheeling […]

The post Alan Alda: Relating Through Improvisation appeared first on Smithsonian Insider.

 This video explains how the Marine and Estuarine Ecology Lab and Fish and Invertebrate Ecology Lab at the Smithsonian Environmental Research Center in Edgewater, […]

The post Chesapeake juvenile oyster study appeared first on Smithsonian Insider.

Highlights of the year 2017 Freer Gallery of Art and Arthur M. Sackler Gallery

The post 2017 Freer|Sackler Year in Review appeared first on Smithsonian Insider.

At the Smithsonian’s National Museum of Natural History, curator of arachnids and myriapods Hannah Wood has examined and analyzed hundreds of pelican spiders both in the field […]

The post Pelican spiders: Ancient assassins that eat their own kind appeared first on Smithsonian Insider.

Josh T. Franco, national collector for Smithsonian’s Archives of American Art, explains a copyright created by Mexican American artists to safeguard their work and reaffirm […]

The post What is Con Safos? appeared first on Smithsonian Insider.

Yesterday, we heard about the hyper-loop, a system that could get you from L.A. to San Francisco in about 30 minutes without losing your eyeballs.

Steve Julian: Business analyst Mark Lacter, that might come in handy given how crowded California's air corridor has become...

Mark Lacter: We'll talk about the hyper-loop in a moment, Steve, but yes, the L.A.-to-San Francisco air route is the busiest in the U.S., and it's already the most competitive.  We're talking about more than 50 flights a day, which - if you spread them out between six in the morning and 10:30 at night - there'd be one flight every 20 minutes.  But, Delta obviously thinks there's room for more because it's announced an hourly shuttle between the two cities.  That's another 14 daily flights beginning September 3.  The airline will be using a somewhat smaller jet, and it sounds as if the focus will be on the business traveler, with free newspapers, wine, and beer.

Julian: How much will it cost, do we know?

Lacter: As usual, it's a lot cheaper if you make an advance purchase, but if you're buying your tickets at the last minute - which is what a lot of business travelers do - roundtrip runs a hefty $430.  Actually, this Bay Area shuttle is just the latest effort by Delta to expand out of LAX, which is different from other major airports in that it doesn't have any one airline that dominates (United has a slight edge in market share over American, with Delta about three percentage points behind).  American also has been adding flights out of LAX.

Julian: Sounds like the airline business is improving...

Lacter: That's what happens when you pack planes to the absolute max, which is bad news for travelers being crammed into coach seats.  But it's good news for LAX, which continues to be the airport of choice among airlines looking to add service - matter of fact, domestic passenger traffic was up almost 8 percent in June compared with a year earlier.  Some of those gains might be at the expense of service elsewhere - most especially Ontario Airport, which has seen a big exodus among airlines and passengers.  Ontario city officials have been trying to regain control of the airport, which has been operated by the city of Los Angeles.

Julian: Back to the hyper-loop - is this kind of transport possible?

Lacter: Well, it's the brainchild of billionaire Elon Musk, and you never say never with this guy.  He started the electric car company Tesla and the private space company Space X.  The hyper-loop is a high-speed system of passenger pods that would travel on a cushion of air (think of air hockey table).  The pods would travel at more than 700 miles per hour, but they wouldn't result in sonic booms that severely restricted the Concorde aircraft.  Of course, anything that promises super-speed travel is bound to get people talking - and, from what the physics professors are saying, the Musk idea seems feasible.

Julian: How would its cost compare to the bullet train?

Lacter: He says a lot cheaper.  The price tag on the train is $70 billion at last check; Musk says he can do his for $6 billion.  But, the issue isn't so much the cost or even the technology, but the politics.  As a rule, governments do not think outside the box, and that's what a project like this is all about.  Already, you have bullet train supporters saying that the hyper-loop is impossible, but what they're really saying is we have a lot riding on the train, and we don't want this guy to mess it up.

Julian: But, how much demand is there for high-speed transport?

Lacter: You'd think there would be a lot, but when Boeing came up with a nifty idea for a souped-up plane that would shave almost an hour from L.A. to New York, the airlines said no because it would require more fuel - and that would mean raising fares.  Musk says his system would be a lot cheaper than traveling by plane, which could be a game changer in the attitudes about going places.  But, those attitudes won't change until the thing is actually built, and that can't realistically happen until attitudes change.  That's the ultimate problem.

Julian: Hence, why we're content to squeeze into coach.

Lacter: Yep.

Mark Lacter is a contributing writer for Los Angeles Magazine and writes the business blog at LA Observed.com.

This content is from Southern California Public Radio. View the original story at SCPR.org.

Across the country, the sale of electric cars is sluggish.

Susanne Whatley: But business analyst Mark Lacter, that's not quite the case in California...

Mark Lacter: Well, comparatively speaking, Susanne.  L.A. and San Francisco alone made up 35 percent of the electric cars sold in the entire U.S. during the first half of the year - 35 percent!  Keep in mind that statewide just 9,700 electric cars were sold in that six-month period, which translates to a little over 1 percent of all car sales in California.  So, they're not exactly lining up around the block, even in a region that's known for its early adopters.  Of course, electric cars were always going to be a tough sell -

Whatley: I've been driving one for about half a year now... and I absolutely love it.  But they ARE expensive, and I'm sure that's a factor.

Lacter: - and that's even after a federal tax credit, but they also require drivers to learn about recharging the battery - sometimes in not-very-convenient places - and, from a design standpoint, most of them don't stand out (one of the automakers that's now out of business had been selling what was a basically plain vanilla Mitsubishi sedan).  Now, the one notable exception is the Tesla - so long as you have at least $90,000 to shell out, and are willing to wait a while to get your car delivered.  In affluent sections of L.A., this is truly the hot car - just 600 or so Teslas have been sold in Southern California during the first seven months of the year.  It's also received rave reviews from all the big automotive publications.

Whatley: And perhaps most surprising of all, Tesla has been making money…

Lacter: That's right, although the stock price is ridiculously overvalued at around $20 billion (that's one-third the market value of General Motors, even though Tesla cranks out all of 21,000 vehicles a year while GM sells almost 5 million).  People seem to love this car almost in spite of it being battery powered, which gets us back to the challenges in trying to sell these things.  Elon Musk, who founded the company (he's also behind SpaceX and he co-founded PayPal), has managed to win over customers because the car itself is so much fun to drive.  The other makers of electric cars - not so much.

Whatley: So, for the folks still on the fence... might it be better to wait until driverless cars become available?

Lacter: That's going to be quite a wait, although all the automakers are working on their versions of self-driving cars.  The Mercedes people just announced plans to launch in 2020 - the same year that Nissan wants to bring out its car - and Google, which has had self-driving cars tooling around California for several years, is looking at 2017.  So, what we're seeing is real, but the question is what sort of real it'll turn out to be.  Certainly, the possibilities are nothing short of revolutionary - you're looking at, potentially, faster commute times because cars will be able to travel closer to one other (reaction times would be faster than with a human behind the wheel); in addition, fewer accidents and injuries (also a function of reaction times).  But, how well the vehicles work once they get beyond the testing phase is anyone's guess.  California does allow self-driving prototypes car for testing purposes, but that's far different than full-scale authorization.

Whatley: What if something goes wrong?

Lacter: That's one of the big concerns - liability, but the real issue is public acceptance.  Already, surveys are finding reluctance to buying a driverless car, or even having them on the road.  That's not a huge surprise considering how novel the concept still is - and all it takes are a few mishaps to affirm the skeptics.  All of which points to a lengthy transition period - not unlike the early days of the passenger plane, when most folks couldn't imagine getting into a flying machine.  Eventually, they got used to them, but it took time.

Whatley: And finally, some thoughts on Cal Worthington?

Lacter: Certainly one of the great showmen in the annals of L.A. broadcasting - Cal Worthington wasn't the first auto dealer to discover the benefits of commercials, but he lasted longer than anyone else, selling more than a million cars (that according to his count), and grossing billions of dollars.  The Worthington ads are sometimes considered the first infomercials - that might be a stretch, but three factors really made it all come together: Southern California's appetite for the automobile, the ease by which Cal could deliver his schtick (remember when he was strapped to the wing of a biplane?), and the fact that there was so much available air time to sell in L.A.. Definitely a legend in his own time.

Mark Lacter writes for Los Angeles Magazine and pens the business blog at LA Observed.com.

This content is from Southern California Public Radio. View the original story at SCPR.org.

It's late October, which means  more and more stores are decorating for Christmas. 

Steve Julian:  Business analyst Mark Lacter, whatever happened to "better late than never?" 

Mark Lacter: Steve, retailers never want to sell late because it often means having to reduce the price. They're looking to start out as soon as possible - these last three months represent their biggest payday of the year. And here in California people do seem to be buying stuff - consumer spending has been up for 14 consecutive quarters, going back to the spring of 2009, and taxable sales are up almost 5 percent from the peak levels before the recession. Another good sign is Chapman University's index of consumer sentiment, which is at its highest level since the beginning of the recession in late 2007. All these indicators explain why the state economy is generally outpacing the rest of the nation.

Julian: There has to be a "but" in here someplace…

 Lacter: The "but" is that only 60 percent of the jobs lost during the downturn have been recovered, and the unemployment rate in many parts of the state, including L.A. County, is still at or above 10 percent, which isn't what you'd call a healthy economy. And that's why holiday shopping this year could end up being sort of hit and miss. Folks who have well-paying jobs and a bunch of their money in the stock market - and Southern California has its share of both - those folks will probably be spending good amounts. 

Julian: Are there geographic tell-tale signs?

Lacter: The closer to the coast you go, the more spending there's likely to be. But it's a different story if you're feeling vulnerable about your job or in the amount of savings you have in the bank. So you have retailers once again coming up with ways of reaching as many budget-conscious folks as possible, as early as possible. The most obvious move is opening their stores on Thanksgiving night - Macy's is the latest of the chains to get a head start on Black Friday (Target, Kohl's, Walmart and J.C. Penney will also be open). Another strategy is matching your prices with the prices on Amazon and other online retailers - also, retailers will use mobile apps and arrange in-store pickup of online purchases. All told, expect holiday sales to run 3 percent ahead of last year, with the L.A. area likely to be a bit higher. Decent, but not great.

 Julian: What's the message to consumers now: buy or not buy?

 Lacter: Well, we'll start with the good news - gasoline prices are at their lowest level since the beginning of the year, with an average gallon of regular in the L.A. area running $3.75, according to the Auto Club. And barring any refinery fires or international catastrophes, the numbers might keep falling into November and December, which could incentivize consumers to buy a little more at the shopping malls. Here's some more good news - the L.A. area has seen a huge drop in the number of homeowners who are underwater, which happens when the value of a property is less than the amount that's owed on the property. This of course was a big problem during the recession, but over the last year the median home values have gone up between 20 percent and 30 percent. 

 Julian: And if your equity is positive instead of negative, you'll probably feel more confident about spending. 

 Lacter: That's right. But there are also deterrents to spending - as has been reported, a few hundred thousand Californians lose their individual health care policies by the end of the year because their plans don't meet the requirements of the Affordable Care Act. Policyholders will be stuck in many cases with a premium increase, possibly a big increase. Now it's possible that in the long run these folks will be better off with a more inclusive plan that results in lower out-of-pocket expenses. But it'a hard to ignore the sticker shock of having to shell out, say, $250 a month instead of $100.

 Julian: There goes the holiday list...

 Lacter: For those folks, yes. And even though L.A. consumers do a good job of separating their feelings about Washington with their desire to spend, the economy is bound to slow down a little. So Steve, just don't count on that $9,000 fur vest I was going to get you for Christmas. Sorry about that…

Mark Lacter writes for Los Angeles Magazine and pens the business blog at LA Observed.com.

This content is from Southern California Public Radio. View the original story at SCPR.org.