Thanks for your information

Joseph X. Zhou — Sun, 07 Oct 2007 16:52:38 -0400

Thanks for your information about the version with explanation, which is exactly what I am looking for. You are absolutely right that the true image of inner space of a cell should be filled with lots of small molecules: water, ligand and various ions Ca+, Na+ etc. Here the video takes some artistic liberties to make it look empty. However, it is good to do so since we can focus on a single mechanis at a time.

Great video of the cell, with explanations

Zhigang Suo — Sun, 07 Oct 2007 07:24:37 -0400

Thank you so much for pointing to this great video. The video highlights some molecular processes. In addition to large molecules featured in the video, should I assume that the space is filled with water or other small molecules?

Here is another version of the same video pointed out by Teng Ti. This version also has accompanying explanation.

4 billion years evolution in 8 min.

Joseph X. Zhou — Sat, 06 Oct 2007 20:06:14 -0400

Recently I saw an animation
named “The inner life of the cell”, which was made by Howard Hughes Medical Institute and Harvard University Biovision. It can be watched online only:

http://aimediaserver.com/studiodaily/harvard/harvard.swf

Watching this animation was so
overwhelming that it is almost a religious
experience for me as a biophysics researcher. What you try to understand in
your day-to-day research is presented to you face to face with such a
miraculous vivacity. Every detail is painfully accurate in each process. I
believe that everybody, who is doing research in molecule biology and molecule
modeling, would be totally overwhelmed by this video.

Even an outsider would be
impressed with its fabulous 3D effect, it is better to know what is really
going on in each process.

At first, the white blood
cell rolls along the inner wall of the blood capillary. After the first zoom-in,
you can see the surface of the white cell ( the bumpy stuffs ). With more zoom-in, the hair stuff, the proteins
on the surfaces of while blood cell, begin to attach themselves on the membrane
protein of the capillary cells.

Later, you will see the ruff
sea, which is just the membrane of the cell. The floating dish is the proteins
to get the message from the receptors and spread it through the white cell. Then
some molecule messengers promote the polymerization of Actin filaments ( the
railway inside the cell for transportation) while other proteins to cut the
filaments in the other end; some other messengers cause the small tube structures to polymerize
forward on one end and break down at the other end. What happened flatten out
the cell and makes it further adhere to the capillary cells, which we can see
later.

It is almost surreal to watch
a molecule motor – Kinesin walking along
the tube while dragging a large bag hundreds times larger than itself.

At the same time, a signal is
sent to the nucleus to produce relevant mRNA, which are passing through pores
in the nucleus membranes. Then they immediately fold into the circle. The large
ribosomes attach themselves to the chain of mRNA, read the information on it
and produce the polymer chain of certain proteins.

These proteins are sorted and
packaged by some macromolecules, then are sent to the membrane of the white
cell. You can see the Kinesins are pulling them towards something like blue
mushrooms (cell membranes). These packages merged with cell membranes and release
the soluble proteins into intercellular space. These release proteins further stimulate
cells to produce more receptors to strength the contact between cells, which
lead the white cell to flatten out and squeeze itself through the capillary
membrane.

If we want to build a
bio-mechanical model of this process, we need to ask ourselves:

* What is the force to flatten the
white cell?

* Could the large deformation
of the white cell be modeled?

* How to deal with the
interactions between the white cell of capillary cells?

Anyhow it is really a wonder
to include the information and logic encoded in 4 billion years evolution and
discovered by the hard-working research in the past 50 years in this 8 minute video.

iMechanica - 4 billion years evolution in 8 min. - Comments

Thanks for your information

Great video of the cell, with explanations

4 billion years evolution in 8 min.