Per Ardua Ad Astra

The beauty of nature is so enthralling, that no amount of words will ever do justice in describing it.

Brought to my attention by Pei Xin, I also present to you this amazing video Cellular Visions: The Inner Life of a Cell. Produced by XVIVO, a scientific animation company in collaboration with Harvard University for use in Harvard’s BioVisions computer-based learning program for undergraduates. The description on studiodaily.com reads : The animation illustrates unseen molecular mechanisms and the ones they trigger, specifically how white blood cells sense and respond to their surroundings and external stimuli.

I hear the "What, another boring science video/lecture/presentation? Yucks!" Just wait until you see the video.

I highly recommend you to go here to view the video, or you can watch the Google Video provided below for expediency.

Unsurprisingly, it got very encouraging feedback from the Harvard students. Unfortunately, this is only a 3 minute excerpt of the full length 8 minute video. I must get the video for my Fundamentals of Biochemistry module next semester!!! And I want the music too!

For some explanation of that you’re seeing, I’ll try my darned best to provide one. If I’m inaccurate in my description, I apologise since I only have my rusty A-Level Biology to rely on.

It starts off with the usual white blood cell (seems to be a macrophage, but I’m not sure) trawling along the sides of a blood capillary with the red blood cells rushing by (here, blood plasma and its constituents are removed for graphical clarity).

Then it shows a closer look at a pseudopodia of the lymphocyte and the endothelial cell, with molecular strands interlocking (adhesion protein binding with its ligand?).

Next is a typical view of a plasma membrane and a demonstration of its fluid mosaic structure before zooming out away into the cell. Along the way, proteins bind together and a signal is sent down to the nucleus, passing through the microfilaments forming the cytoskeleton along the way (actin?) and you can also see links breaking due to enzymes (cofilin) binding to it. Don’t know if they self aggregate without enzymes to help them along. Next up is the green microtubule subunits self assembling, then dissembling into larger subunits (intermediate filaments?).

After that is probably the most dramatic view of a lipid globule being steadily pulled along a microtubule by a kinesin towards the negative end of the microtubule. Yes, the globular heads of kinesin actually walk the walk! However, I’m not sure if it’s a straight line motion along the microtubule or if it goes in a spiral upwards. In another frame you get to see the nucleus, smooth endoplasmic reticulum (SER) on the lower right and two mitochondrions at either side. And yes, you’ll most likely spot the microtubule organising centres (MTOC) from the very start.

The video goes on with mRNAs emerging from nuclear pores and then forming a loop in the cytoplasm where the 5′ cap joins up with the Poly(A) tail. Consequently, the large and small ribosomal subunits attach to the mRNA and translation occurs.

Moving on, it apparently shows the 5′ cap detached from the mRNA and being bound by another (unknown) molecule in an intricate dance across the intracellular medium with the mitochondrion hovering behind.

After that is just translation occurring on the surface of the SER, transport vesicles budding off from the SER, beginning its journey to the Golgi apparatus with the dynein walking away. I think a simplification also occurs here because microtubules are also supposed to play a role in transport of vesicles but are not shown here.

Next, the Golgi apparatus pulsating. Enough said.

Then, what looks like a transport vesicle on its way to the cellular membrane and merging with it. A group of membrane protein joins up and a ‘platform’ forms under it by some molecules in the membrane (cholesterol?). Then the strands (glycocalyx?) on the proteins extend through some sort of cage and connect with the strands protruding from the endothelial cells.

In the end, the white blood cell rolls to a gap in the endothelium, flattening in the process and squeezing through the blood capillary into tissue.

P.S. This webpage talks about how the animation came about. Plus, this will be an interesting tidbit. From this press release, “Furthermore, preliminary evaluation shows that using animations as a part of their study resource enhances performance on questions requiring data interpretation followed by hypothesis building in the cellular context by almost 30%,” says Dr. Lue. Damm straight!

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