Tag Archives: Caltech

Why DNA is like a phone cable (Recap of a Talk by Prof. Jacqueline Barton)

[Computer rendering of DNA. Via Caroline Davis2010 on Flickr & CC 2.0] 

The Talk:

“DNA-mediated Signaling with Metalloproteins”

In Plain English:

DNA can conduct electricity–like metal wire–and that helps the cell life

The Speaker:

Jacqueline Barton of Caltech

The Sponsor:

MIT Inorganic Chemistry (invited by the grad students)

What It Covered:

When Jacqueline Barton’s lab began publishing papers claiming that DNA can conduct electricity, many of her colleagues didn’t believe them. But in experiment after experiment, they kept finding that they could send small amounts of electricity–much lower than the amount that flows through your charger cord–from an electrode on one end of a DNA strand through to the other.

The exceptions were stretches of DNA with “missense mutations“, hiccups in the genetic code that violated the rule of “G” aligns with “C” and “A” aligns with “T”.

A,T, G, and C are biologists’ shorthand for four small molecular structures– adenine, thymine, guanine, and cytosine– that repeat over and over again along DNA’s backbone. It just so happens that a G-C pair takes up exactly the same amount of space and adds exactly the same amount of twist as an A-T pair.  Anything else–a misplaced guanine, a broken cytosine, or a chemical tag on thymine– throws the DNA’s twist out of whack. And apparently,  the missense mutations also blocked electrical currents’ flow through a tiny gap in the center of the DNA.  Mismatched base pairs or base pairs that were even slightly damaged blocked the electrons’ path. Continue reading “Why DNA is like a phone cable (Recap of a Talk by Prof. Jacqueline Barton)” »

Caltech grows miniature “river deltas” in a lab

About half a billion people live on fan-shaped floodplains that form where rivers meet the sea.

Those plains, called river deltas, share the same fan-like shape the world over. Even after controlling for factors like the size of the river, the slope of the land its channel traverses, and the makeup of the local soil, river deltas have a remarkably consistent shape.

Seriously. Here’s The Nile: [satelite image via NASA Godard Space Flight Center’s Flickr]

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Here’s the Yukon River in Alaska [satelite image via NASA Godard Space Flight Center’s Flickr] 

Image acquired September 22, 2002 Countless lakes, sloughs, and ponds are scattered throughout this scene of the Yukon Delta in southwest Alaska. One of the largest river deltas in the world, and protected as part of the Yukon Delta National Wildlife Refuge, the river's sinuous waterways seem like blood vessels branching out to enclose an organ. Credit: NASA/USGS/Landsat NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram
Image acquired September 22, 2002
Countless lakes, sloughs, and ponds are scattered throughout this scene of the Yukon Delta in southwest Alaska. One of the largest river deltas in the world, and protected as part of the Yukon Delta National Wildlife Refuge, the river’s sinuous waterways seem like blood vessels branching out to enclose an organ.
Credit: NASA/USGS/Landsat
NASA image use policy.
NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission.
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Continue reading “Caltech grows miniature “river deltas” in a lab” »