Thursday, May 19, 2016

myakka state park

ocala national forest

Look, Ma! No Mitochondria

Scientists have found a microbe that does something textbooks say is impossible: It's a complex cell that survives without mitochondria.
Mitochondria are the powerhouses inside eukaryotic cells, the type of complicated cell that makes up people, other critters and plants and fungi. All eukaryotic cells contain a nucleus and little organelles — and one of the most famous was the mitochondrion.
"They were considered to be absolutely indispensable components of the eukaryotic cell and the hallmark of the eukaryotic cell," says Anna Karnkowska, a researcher in evolutionary biology at the University of British Columbia in Vancouver. Karnkowska and her colleagues describe their new find in a study published online Thursday in the journal Current Biology.
Mitochondria have their own DNA, and scientists believe they were once free-living bacteria that got engulfed by primitive, ancient cells that were evolving to become the complex life forms we know and love today.
For decades, researchers have tried to find eukaryotic cells that don't have mitochondria — and for a while they thought they'd found some. One example is Giardia, a human gut parasite that causes diarrhea. It was considered to be a kind of living fossil because it had a nucleus but didn't seem to have acquired mitochondria. But additional studies on Giardia and other microbes showed that actually, the mitochondria were there.
"It turned out that all of them actually had some kind of remnant mitochondrion," says Karnkowska, who notes that mitochondria perform key jobs in the cell beyond just generating power.
A biggie is assembling iron-sulfur clusters for certain proteins, which is thought to be a mitochondrial function that's really essential. So even if a microbe powers itself in a different way and has a limited form of the organelle that isn't the same as the mitochondria found in people, Karnkowska says, "it's still a mitochondrion and it has some important function for the cell."
That kind of vestigial mitochondrion is what she expected to find when she was a researcher at Charles University in Prague and started investigating a particular gut microbe that had been isolated from a researcher's pet chinchilla.
After she and her colleagues sequenced the gut microbe's genome, however, they found no trace that it made any mitochondrial proteins at all. "So that's a great surprise for us," she says. "That should theoretically kill the cell — it shouldn't exist."
What they learned is that instead of relying on mitochondria to assemble iron-sulfur clusters, these cells use a different kind of machinery. And it looks like they acquired it from bacteria.
The researchers say this is the first example of any eukaryote that completely lacks mitochondria.
Michael Gray, a biochemist at Dalhousie University in Halifax, Nova Scotia, says the researchers have made a "compelling" case that they have a bona fide eukaryote without any vestige of a mitochondrion; he calls the finding "unprecedented."
"The observation is significant, in that it clearly demonstrates that a eukaryote can still be a eukaryote without having a mitochondrion," he tells Shots via email.
However, the results do not negate the idea that the acquisition of a mitochondrion was an important and perhaps defining event in the evolution of eukaryotic cells, he adds.
That's because it seems clear that this organism's ancestors had mitochondria that were then lost after the cells acquired their non-mitochondrial system for making iron-sulfur clusters.
"This is not the missing link of eukaryotic evolution," agrees Mark Van Der Giezen, a researcher in evolutionary biochemistry at the University of Exeter in the United Kingdom.
Still, he says, it is an example of how flexible life is.
"It lives in an area without oxygen and therefore can get rid of a lot of biochemistry that you and I would need in our cells to survive," says Van Der Giezen. "This organism managed to adapt in such a way that it could lose an organelle, which every textbook will tell you is an essential feature of eukaryotes. That's pretty amazing. It shows you that life is extremely creative in finding a way to eke out an existence." npr

Meet The Tiny Critters Thriving In Your Carpet, Kitchen And Bed

With the weather warming, it's the season for spring cleaning. But before you reach for the broom and mop, consider who else is sharing your home. The variety of uninvited guests in your dustpan may surprise you.
A recent study published in the journal PeerJ took up the challenge of cataloging the large numbers of tiny animals — arthropods — that live in modern human dwellings. In 50 houses in and around Raleigh, N. C., the research team found about a hundred different species of arthropods in each home. The tally included familiar types — like flies, spiders and ants — but also some species that are less well known, such as gall wasps and book lice.

Grains of uncooked rice dwarf this book louse. Though book lice thrive in most human homes, they largely go unnoticed.

The Joy Of Seeing Your Gooey Innards

18 seconds of embodied cosmic weirdness. It's an MRI of baritone Michael Volle singing Wagner's "O du, mein holder Abendstern" (Oh Thou, my fair evening star). It's both beautiful and gross at the same time, which is exactly the point. Even our highest aspirations are always grounded in the raw stuff of the world.

4 Things To Know About Hillary Clinton's Approach To Foreign Policy

As a former senator and secretary of state, Hillary Clinton has a long foreign policy track record. That record suggests she'd be more hawkish than President Obama — and many of her fellow Democrats. But don't expect her to go overboard. She knows all too well the political price that can come with military intervention.
Here are four things to know about Clinton's approach to foreign policy:
(We've previously broken down Donald Trump's and Bernie Sanders'approaches to foreign policy.)
1. She's experienced
2. She's more hawkish than President Obama
3. She might not be that hawkish
4. She's concerned about alliances

1. She's experienced
If Clinton is elected, she'll have more foreign policy experience than any president since George H.W. Bush. She traveled extensively as first lady and as a senator and logged nearly a million miles visiting 112 countries as secretary of state. "Hillary Clinton is really the rare candidate with a long track record," said Elizabeth Saunders, a visiting fellow at the Council on Foreign Relations.
The former secretary will try to make that background an asset in the campaign, arguing the country can ill afford a president who needs on-the-job training. "Our new commander in chief will walk into the Oval Office and find a world of hard choices and tough problems," Clinton told an audience at Stanford this spring. "So the stakes could not be higher."
2. She's more hawkish than President Obama
Clinton is less reticent when it comes to deploying military force than President Obama. While she hasn't advocated large-scale ground operations, she has pushed for the creation of "safe zones" in Syria, and she was a strong advocate for the U.S. military intervention in Libya. "Her default preference seems to be for action," Saunders said. "People have described her as having a preference for being 'caught trying.' She'd rather do something and be criticized for it than be criticized for doing nothing at all." That distinguishes Clinton's foreign policy approach from Obama's, whose instinctive caution has been summed up by the phrase, "Don't Do Stupid [Stuff]."
3. She might not be that hawkish
If Obama's caution is, in part, a reaction to the excesses of the George W. Bush era, Clinton's more aggressive posture might reflect a reversion to the mean. But don't expect her to go overboard. After all, she paid a political price for backing Bush's invasion of Iraq in 2003, as well as the Libyan intervention in 2011, which left a violent vacuum in which four Americans were later killed in Benghazi.
"Given the fact that many of her decisions to use military force have come back to haunt the United States generally and Hillary Clinton specifically, she may well have to temper some of those hawkish instincts in the service of prudence. And the reality is that we have very bad options," said veteran Middle East diplomat Aaron David Miller of the Woodrow Wilson Center. Clinton has criticized some of the more hawkish proposals from Republican candidates for indiscriminate bombing of ISIS. "Proposing that doesn't make you sound tough. It makes you sound like you're in over your head," Clinton said at Stanford. "Slogans aren't a strategy. Loose cannons tend to misfire. What America needs is strong, smart, steady leadership to wage and win this struggle."
4. She's concerned about alliances

Compared to her remaining presidential rivals Donald Trump and Bernie Sanders, Clinton is a committed internationalist. "For decades, Republican and Democratic administrations have understood that America's alliances make us stronger," Clinton told the Stanford audience in March. "Turning our back on our alliances or turning our alliance into a protection racket would reverse decades of bipartisan American leadership and send a dangerous signal to friend and foe alike."
Erstwhile Republican White House hopeful Carly Fiorina complained that all of Clinton's globetrotting as secretary of state produced little in the way of concrete agreements. But the Council on Foreign Relations' Saunders says that's too simplistic. "Diplomacy is important but it's not always dramatic," Saunders said. "Most high-level diplomatic travel by the president or secretary of state is really about tending to relationships." npr