Текст 5. Jump-Starting the Orbital Economy

By David H. Freedman

The shuttle is out. When NASA retires the space shuttle in the middle of next year, the U.S. will no longer be able to launch astronauts or supplies to the International Space Station.

Private companies are in. The Obama administration has canceled Constellation, the planned successor to the shuttle, and instead plans to rely on private companies to ferry astronauts.

Hopes are high. In theory, early government support of daring entrepreneurs could jump-start a vibrant economy centered on space travel, with competition pushing prices ever lower.

Risks are, too. Yet no one knows if start-up companies will be able to deliver safe, affordable, reliable spacecraft. If they fail, human exploration of space could be set back by decades.

Two years ago deceased Star Trek actor James “Scotty” Doohan was granted one last adventure, courtesy of Space Exploration Technologies Corporation. SpaceX, a privately funded company based in Hawthorne, Calif., had been formed in 2002 with the mission of going where no start-up had gone before: Earth orbit. In August 2008 SpaceX loaded Doohan’s cremated remains onto the third test flight of its Falcon 1, a liquid oxygen- and kerosene-fueled rocket bound for orbit. Yet about two minutes into the flight Doohan’s final voyage ended prematurely when the rocket’s first stage crashed into the second stage during separation. It was SpaceX’s third failure in three attempts.

Well, what did you expect? Sneered old NASA hands, aerospace executives and the many others who hew to the conventional wisdom that safely ushering payloads and especially people hundreds of kilometers above Earth is a job for no less than armies of engineers, technicians and managers backed by billions in funding and decades-long development cycles. Space, after all, is hard. A small, private operation might be able to send a little stunt ship wobbling up tens of kilometers, as entrepreneur-engineer Burt Rutan did in 2004 to win the X-Prize. But that was a parlor trick compared with the kinds of operations NASA has been running over the years with the space shuttle and International Space Station. When you’re going orbital, 100 kilometers is merely the length of the driveway, at the end of which you’d better be accelerating hard toward the seven kilometers a second needed to keep a payload falling around Earth 300 kilometers up.

(From: “Scientific American”, December, 2010)

Текст 6. Drug-Resistant Genes Spread among Bacteria

By Katherine Harmon

In the fight to stay alive, many bacteria, such as MRSA, have developed resistance to commonly used antibiotics. But other bacteria are using a more insidious type of resistance: that imbued by transferable genes, which can spread among commonly circulating strains.

One of these genetic elements, NDM-1 (New Delhi metallo-beta-lactamase 1), is an enzyme-based defense that renders a bacterium immune to beta-lactam-based antibiotics, which include penicillin, as well as carbapenems (often used as a last resort antibiotic against Escherichia coli infections), cephems (such as cephalosporins and cephamycins) and monobactams, making treatment extremely difficult. The trait was first identified in 2008, and instances of NDM-1–positive infections are now not uncommon in India, Pakistan and Bangladesh. Cases also have been documented in Brazil, Canada, Japan, the U.K. and the U.S.

A new essay published in the December 16 issue of The New England Journal of Medicine revisits the issue, highlighting the potential that NDM-1 and other antibiotic-busting genes have to disable much of our current pharmaceutical arsenal.

“The spread of these organisms has prompted widespread concern because some of them are resistant to all antimicrobial agents except the polymyzins,” Robert Moellering, of Harvard Medical School and Beth Israel Deaconess Medical Center, wrote in the perspective piece.

Initial cases of NDM-1 seemed to be only found among patients who had received medical care in India, where antibiotic use is less regulated. But more recent findings have suggested some NDM-1–positive patients in the U.K. might have picked up a resistant strain without traveling abroad.

These genes do not need an exotic infection to wreak havoc in a patient. They can be picked up by “all sorts of bugs we’re all walking around with in our guts,” says Brandi Limbago, of the Division of Healthcare Quality Promotion at the U.S. Centers for Disease Control and Prevention. But once the resistant genetic material enters the bacterium, “it produces an enzyme that attacks the antibiotic and makes it nonfunctional – they basically chew it up,” she explains. These infections are not always deadly, but “in the right host,” such as one with a weakened immune system or inserted medical equipment (including catheters), “those patients become infected with these organisms,” Limbago says. “And if you don’t have the right tools to treat them, that’s when you run into trouble.”

Newer antibiotics, such as cephalosporins and carbapenems as well as beta-lactamase inhibitors, seemed like an effective strategy against these bacterial tactics. But these have “simply been met with the evolution of new beta-lactamases, often through mutations, that inactivate these antibiotics,” Moellering wrote. Currently, there are some 890 such known enzymes, “far more than the antibiotics developed to combat them.”

Indeed, Limbago warns, “all carbapenem-resistant Enterobacteriaceae are bad – it’s not just NDM-1 that should have us worried.” And although NDM-1 might be grabbing more headlines globally, Limbago explains that here in the U.S., another enzyme, Klebsiella pneumoniae carbapenemase, has been a much bigger concern. And, as Moellering noted in his essay, another class, known as CTX beta-lactamases, “at the very least will compromise our ability to use beta-lactam antibiotics to treat community-acquired urinary tract infections.”

(From: “Scientific American”, December, 2010)