Radiation hotspot in Tokyo linked to mystery bottles

A radiation hotspot has been detected in Tokyo seven months into Japan’s nuclear crisis, but local officials said on Thursday high readings appeared to be coming from mystery bottles stored under a house, not the tsunami-crippled Fukushima atomic plant.

The Fukushima Daiichi nuclear power plant, struck by a devastating quake and tsunami in March, has released radiation into the atmosphere that has been carried by winds, rain and snow across eastern Japan.

Officials in Setagaya, a major residential area in Tokyo about 235 km (150 miles) southwest of the plant, said this week it found a radioactive hotspot on a sidewalk near schools, prompting concerns in the country’s most populated area far from the damaged nuclear plant.

The radiation measured as much as 3.35 microsieverts per hour on Thursday, higher than some areas in the evacuation zone near the Fukushima plant, the center of the world’s worst nuclear disaster since Chernobyl 25 years ago.

But the local government found several bottles under the floor of a nearby house emitting high levels of radiation.

“A measuring device, when pointed at them, showed very high readings. Radiation levels were even exceeding the upper limit for the device,” Setagaya Mayor Nobuto Hosaka told a news conference.

Officials from the Education Ministry are now looking into the matter, including the contents of the bottles.

via Radiation hotspot in Tokyo linked to mystery bottles | Reuters.

Rare “Cyclops” Shark Found

Talk about a one-of-a-kind discovery—an extremely rare cyclops shark (pictured) has been confirmed in Mexico, new research shows.

The 22-inch-long (56-centimeter-long) fetus has a single, functioning eye at the front of its head—the hallmark of a congenital condition called cyclopia, which occurs in several animal species, including humans.

Earlier this year fisher Enrique Lucero León legally caught a pregnant dusky shark near Cerralvo Island (see map) in the Gulf of California. When León cut open his catch, he found the odd-looking male embryo along with its nine normal siblings. “He said, That’s incredible—wow,” said biologist Felipe Galván-Magaña, of the Interdisciplinary Center of Marine Sciences in La Paz, Mexico.

Once Galván-Magaña and colleague Marcela Bejarano-Álvarez heard about the discovery—which was put on Facebook—the team got León’s permission to borrow the shark for research. The scientists then x-rayed the fetus and reviewed previous research on cyclopia in other species to confirm that the find is indeed a cyclops shark.

Cyclops sharks have been documented by scientists a few times before, also as embryos, said Jim Gelsleichter, a shark biologist at the University of North Florida in Jacksonville. The fact that none have been caught outside the womb suggests cyclops sharks don’t survive long in the wild.

Overall, finding such an unusual animal reinforces that scientists still have a lot to learn, Gelsleichter added.

“It’s a humbling experience to realize you ain’t seen it all yet.”

(See “Cyclops Myth Spurred by ‘One-Eyed’ Fossils?”)

—Christine Dell’Amore

via Pictures: Rare “Cyclops” Shark Found.

From blue whales to earthworms, a common mechanism gives shape to living beings

Why don’t our arms grow from the middle of our bodies? The question isn’t as trivial as it appears. Vertebrae, limbs, ribs, tailbone … in only two days, all these elements take their place in the embryo, in the right spot and with the precision of a Swiss watch. Intrigued by the extraordinary reliability of this mechanism, biologists have long wondered how it works. Now, researchers at EPFL Ecole Polytechnique Fédérale de Lausanne and the University of Geneva Unige have solved the mystery.

Their discovery will be published October 13, 2011 in the journal Science.The embryo is built one layer at a timeDuring the development of an embryo, everything happens at a specific moment. In about 48 hours, it will grow from the top to the bottom, one slice at a time — scientists call this the embryo’s segmentation. “We’re made up of thirty-odd horizontal slices,” explains Denis Duboule, a professor at EPFL and Unige. “These slices correspond more or less to the number of vertebrae we have.”

Every hour and a half, a new segment is built. The genes corresponding to the cervical vertebrae, the thoracic vertebrae, the lumbar vertebrae and the tailbone become activated at exactly the right moment one after another. “If the timing is not followed to the letter, you’ll end up with ribs coming off your lumbar vertebrae,” jokes Duboule. How do the genes know how to launch themselves into action in such a perfectly synchronized manner? “We assumed that the DNA played the role of a kind of clock. But we didn’t understand how.”When DNA acts like a mechanical clockVery specific genes, known as “Hox,” are involved in this process. Responsible for the formation of limbs and the spinal column, they have a remarkable characteristic. “Hox genes are situated one exactly after the other on the DNA strand, in four groups. First the neck, then the thorax, then the lumbar, and so on,” explains Duboule. “This unique arrangement inevitably had to play a role.”

The process is astonishingly simple. In the embryo’s first moments, the Hox genes are dormant, packaged like a spool of wound yarn on the DNA. When the time is right, the strand begins to unwind. When the embryo begins to form the upper levels, the genes encoding the formation of cervical vertebrae come off the spool and become activated. Then it is the thoracic vertebrae’s turn, and so on down to the tailbone. The DNA strand acts a bit like an old-fashioned computer punchcard, delivering specific instructions as it progressively goes through the machine.”A new gene comes out of the spool every ninety minutes, which corresponds to the time needed for a new layer of the embryo to be built,” explains Duboule. “It takes two days for the strand to completely unwind; this is the same time that’s needed for all the layers of the embryo to be completed.”

This system is the first “mechanical” clock ever discovered in genetics. And it explains why the system is so remarkably precise. …

The process discovered at EPFL is shared by numerous living beings, from humans to some kinds of worms, from blue whales to insects. The structure of all these animals — the distribution of their vertebrae, limbs and other appendices along their bodies — is programmed like a sheet of player-piano music by the sequence of Hox genes along the DNA strand.

The sinuous body of the snake is a perfect illustration. A few years ago, Duboule discovered in these animals a defect in the Hox gene that normally stops the vertebrae-making process.

“Now we know what’s happening. The process doesn’t stop, and the snake embryo just keeps on making vertebrae, all identical, until the process just runs out of steam.”

The Hox clock is a demonstration of the extraordinary complexity of evolution.

via From blue whales to earthworms, a common mechanism gives shape to living beings.

A little DNA tweaking and we could have some awesome human snake people.