Science-- there's something for everyone

Monday, November 30, 2009

Glowing Cells

Talk about being red-blooded!
A team of scientists led by Professors Andrew Elefanty and Ed Stanley have modified a human embryonic stem cell line so that it glows red when the cells differentiate into red blood cells.
Stem cells are valued for their ability to turn into any cell type. The difficulty is in coaxing them to become the kind of cell you need at the moment.
This new cell line will fluoresce when the hemoglobin genes are turned on, allowing scientists to observe and possibly learn to control that process.

Raptors Strike

Here’s a story that begins and ends with feet.
A trio of Montana State University graduate students (Denver Fowler—no I didn’t make that up, Elizabeth Freedman and John Scannella) has completed a study of raptor feeding methods. Raptors are carnivorous birds, also called ‘birds of prey’, including eagles, hawks, owls and falcons.
The students began with a box of birds’ feet stored at the Museum of the Rockies, hoping to use the feet to determine the birds’ killing methods. Not surprisingly, the talons sizes and shapes determined how the birds held and killed their prey. What was surprising, at least to the MSU students, was that no one had studied this before.
It turns out that owls, which mainly eat small prey, rely on constricting the prey in their grips, whereas eagles and hawks, as hunters of larger animals, dig their larger talons deep into their prey and proceed to dismember it with their beaks.
The students were originally interested in studying dinosaurs, not birds. They had hoped the box of birds’ feet would lead to insights into dinosaur feeding patterns. Now that the connection between the size and shape of feet and killing method is better understood, scientists can reexamine carnivorous dinosaur feet.

Recreating the RNA World

RNA molecules are formed using nothing but water.

Abiogenesis is the study of how life began on earth. This is not to be confused with evolution, which explains how we came to have the current diversity of life. Evolution began once there were life forms reproducing and competing. But how did life originally arise? That is still not completely understood.

We do know a few things though, one of which is that RNA preceded DNA as the information carrying molecule. RNA is less stable than DNA, but it has the advantage of serving as both a vehicle for information storage and as a catalyst to make more RNA and even protein chains. The instability of RNA means that primitive life forms employing it would have had a much greater mutation rate. This might have been advantageous to life in the early stages when it was struggling to gain footholds (pseudopod holds?) on its environment. As soon as life discovered DNA, a much more stable molecule, RNA was abandoned as the primary information storage container.

This is all well and good, but how do you get RNA in the first place? Ernesto Di Mauro’s lab has been able to synthesize chains of RNA over 120 nucleotides long using only water. That’s right, no enzymes or inorganic catalysts, no radiation, no lightning bolts. And of course, once you have RNA and a few odds and ends like lipids, you can have primitive cells!