DNA photos

TEM image with intensity profile of λ-DNA fibers.

With all the hassle about endangered shark species in fin samples and continuous mislabelling of fish products I almost forgot to share what I thought are the pictures of the week.

Researchers from Italy were able to do direct imaging of double stranded λ-DNA in the A conformation, obtained by combining a novel sample preparation method based on a super hydrophobic DNA molecule self-aggregation process with transmission electron microscopy (TEM). A-conformation DNA is thought to be one of three biologically active double helical structures along with the conformations B and Z. It is a right-handed double helix fairly similar to the more common and well-known B form, but with a shorter more compact helical structure. 

A-DNAs superstructures used for image simulations

This is the first time that humans have captured direct photos of DNA. At present, the method only works with superstructures of DNA made up of six molecules wrapped around an seventh acting as a core. That's because the electron energies are high enough to break up a single DNA molecule. However, according to the researchers the problem could likely be solved by using a lower-power electron scope. With this technique, researchers should be able to see how single molecules of DNA interact with other biomolecules.

How cool is that?