Fossil sheds light on lizard-snake divide

The origin of snakes is a perplexing matter. Although DNA analysis suggests that snakes are related to monitor lizards and iguanas, they are anatomically more similar to a group of earthwormlike creatures called worm lizards. Now a new study helps clear the confusion, suggesting that worm lizards are related not to snakes, but to lacertids, a group of limbed lizards found in Europe, Africa and Asia.

Writing in the journal Nature, researchers identify a 47-million-year-old fossilised lizard in Germany that appears to be a common relative to both lacertids and worm lizards.
“This was the transitionary animal; it was exactly what we were looking for,” said Johannes Mueller, a paleozoologist at the Natural History Museum in Berlin and the study’s first author.

“It indirectly implies that identifying burrowing worm lizards with snakes is a mistake.”
Mueller and his co-authors used X-ray computed tomography, or CT scans, to study the skull of the fossilised lizard and compare it with those of living lizards and snakes. They found that the fossilized lizard had a thickened, capsulelike skull with no external ear opening, similar to worm lizards.

The fossil was discovered in Messel Pit, a fossil site near Frankfurt and a UNESCO World Heritage Site. The lizard, named Cryptolacerta hassiaca, is less than 3 inches in length and is the only known specimen of its kind.

Sindya N Bhanoo, New York Times News Service

Clue to cosmic rays’ origin

A fresh study of the remnant of a star explosion—Tycho supernova—first observed in 1572, has revealed a pattern of stripes not seen before. This could be responsible for Earth-bound cosmic rays. The rays have a primary role in formation of lithium, beryllium, and boron in the universe.

They also produce some radioisotopes on Earth like carbon-14. The remnant was first observed by a Danish astronomer Tycho Brahe, and was the result of an explosion of a white dwarf star about 13,000 light years from Earth, within the Milky Way.

Down to Earth Features

A nano cure for cancer

Imagine a future when magnetic particles less than 100 nanometers in diameter will target, detect and capture images of cancer cells in your body. A team from the Indian Institute of Technology (IIT), Kharagpur, thinks such a future is possible. Researchers designed nanoparticles that can be used to transport drug molecules in the body. Iron oxide nanoparticles are emerging as coveted magnetic nanomaterials for their ability to enter the body without causing toxic effects and staying long in the blood circulatory system.

The researchers first produced iron oxide nanoparticles and modified them with chitosan, a polysaccharide found in shellfish and organic compounds. The modified particles were then studded with dye molecules with fluoroscent property, to study their imaging capacity. They were tagged with folic acid for selective targeting of cancer cells. Most human cancer cells express cell surface proteins or receptors that have an affinity for folic acid.

To study the role of folic acid in targeting cancer cells, researchers cultured human cervical cancers cells and fibroblast cells (in animals), with the nanoparticles. It was found that folate receptors facilitate the entry of nanoparticles into the body. This was why the cervical cancer cells had more nanoparticles than the normal cells.

The fluorescent nanoparticles also showed their potential to be used as magnetic resonance imaging agents in capturing images of cancer cells. “These nanoparticles can be enhanced further with therapeutic properties. This can be done by encapsulating drug molecules to design a multifunctional probe for detection as well as therapy in the near future,” said Panchanan Pramanik, lead researcher from IIT, Kharagpur. The research was published in Nanoscale.

Biplab Das, Down To Earth Features

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