Dr. William S. Harris saw the new video in our series on molecular machines, "The Workhorse of the Cell: Kinesin," and had this notable comment. He reminds us that despite the fantastic animation, the world of the cell is a world of darkness. Professor Harris teaches in the Department of Internal Medicine, Sanford School of Medicine, University of South Dakota:

This video animation of the "workhorse of the cell" is spectacular in its production, but even more so in the intricate design it illustrates. The operation of this "protein backpacker" is even more amazing when one considers that this (along with the activities of all other molecular machines in the cell) happens in absolute darkness. Kinesin cannot "see" (like we can in watching the video) the microtubule that it is traversing. Like a blind tightrope walker, this wonderful apparatus faithfully delivers its cargo and then waits for its next assignment. No doubt hundreds of scientists have spent years unraveling how kinesins work, and this clip is a testimony to their skills and perseverance as well.