Tag Archives: ifl science

Ancient Virus Revived From 700-Year-Old Caribou Feces

Sounds like something stupid to start a zombie apocalypse movie…

October 28, 2014 | by Janet Fang

photo credit: An ice core containing ancient caribou feces. Caribou DNA, digested plants, and viruses were frozen within layers of ice for thousands of years, enabling researchers to detect the genomes of ancient viruses / Brian Moorman

Researchers have reconstituted a viral genome from centuries-old caribou feces frozen in the subarctic, and they’ve used the ancient viruses to infect lab plants. The findings, published in Proceedings of the National Academy of Sciences this week, offer a rare glimpse of viral evolution.

Ancient viruses provide snapshots of past diversity and a way to trace viral evolution, but their concentrations are low and intact samples are rarely successfully isolated from the environment. Cryogenically preserved samples in nature may be an untapped repository of preserved ancient viral genetic material.

A team led by Eric Delwart from the University of California, San Francisco, analyzed viral genetic material contained in an ice core obtained by drilling through layers of accumulated caribou feces up to 4,000 years old in a permanent ice patch in the Northwest Territories of Canada. Caribou gather on ice patches to escape pesky flying insects and heat in the summertime. After eating nearby veggies, they deposit feces that contain their DNA, partially digested plant material, as well as viruses—which can remain frozen for millennia. Here’s an aerial photograph of one such caribou congregation:

From a 700-year-old layer of the ice core, the team isolated the complete small circular genome of a DNA virus that was distantly related to plant and fungi-infecting viruses today. They named it aCFV, for ancient caribou feces associated virus. They also isolated a partial viral RNA genome that was related to an insect-infecting virus. They call this one Ancient Northwest Territories cripavirus, or aNCV.

These never-before-seen viruses either originated in plants eaten by caribou or insects attracted to fecal matter, and they were preserved at constant freezing temperatures within protective viral capsids.

The team used a “reverse genetic approach” to reconstitute the genome of the DNA virus. Then, to confirm that the virus infects plants, they inoculated the tobacco relative Nicotiana benthamianawith the ancient viral DNA. The inoculated plants displayed evidence of infection: The DNA virus replicated and systemically spread in the inoculated leaves (orange arrow) as well as their newly emerging leaves (white arrow).

As far as Delwart can tell, these viruses aren’t dangerous, NPR reports. But as the climate warms and more ice melts, more caribou poo infected with ancient viruses might be making its way into the modern ecosystem.

Images: Brian Moorman (top), Glen MacKay (middle), Li-Fang Chen (bottom)

 

 

 

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Bizarre Human Brain With No Wrinkles Discovered

October 31, 2014 | by Kristy Hamilton

photo credit: An adult human brain with no folds. Image Credit: Adam Voorhes. http://www.voorhes.com/

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While photographing shelves of human brains stored away in a closet at the University of Texas for his next book, Adam Voorhes happened upon a truly unique find: a brain with no folds.

David Dexter, scientific director at Parkinson’s UK Brain Bank, told New Scientist that he had never seen an adult brain like this before: “We do get the odd individual where certain sulci are missing but nothing to the extent of this brain.”

The lack of grooves (sulci) and folds (gyri) that characterize a human brain are due to a rare condition called lissencephaly. The disorder is caused by abnormal neuronal migration during embryonic development.

Image Credit: Adam Voorhes. Book: Malformed: Forgotten Brains of the Texas State Mental Hospital. The smooth brain is on the bottom, second to the right.

To learn more about this rare find, Voorhes spent over a year trying to hunt down the details of this and the approximately 100 other human brains in the collection. He sifted through a century’s worth of documents and found a history rife with battle for ownership of the collection. However, nothing about the specific individual came to light.

People with similar though less extensive forms of lissencephaly often experience difficulty swallowing, muscle spasms, seizures, and learning difficulties. Many individuals with this condition die before the age of 10.

All the brains in the collection are from patients at the Austin State Mental Hospital and were subsequently preserved in jars of formaldehyde. For more than 20 years, the brains were forgotten about in a dark closet somewhere in the back of an animal lab. While all the rediscovered brains are considered disfigured or abnormal in some way, a brain with so few folds and grooves is a rarity amongst the rare.

Image Credit: Adam Voorhes. Book: Malformed: Forgotten Brains of the Texas State Mental Hospital

Currently, the University of Texas is working on documenting the brains in more detail with an MRI scanner. Upon conclusion, the brains will be put on display at the Imaging Research Center on campus.

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