Viral concentrates, also known as liquid gold.

My job, besides the field work, was to create a library of viral concentrates and calculate the abundance of virus like particles and bacterial cells in each sample.  The viral concentrates would be used later in RAPD-PCR to provide a general image of the community composition over time, and in conjunction with the abundance counts, I can get an idea of whether the amount of microbes is changing, just the community, or both.

VCs, or Viral Concentrates

Seriously, I treasure viruses.  A viral concentrate provides invaluable information about the Grim Dell at a very specific time point, and without my VCs, I would know far less about the GD.  

To put it simply, viral concentrates are created by filtering the aquatic sample through a .22um filter in order to reduce contaminants as much as possible without eliminating the ever-so-important viruses.

The filtrate is then transferred to ultracentrifuge tubes, balanced, and placed in the ultracentrifuge.  The speed of the ultracentrifuge causes the viruses to pellet at the bottom of each tube.  I remove the supernatant and resuspend the pellets in TMG buffer. After the resuspension, the VCs are stored at 4 degrees Celsius until I’m ready to do RAPD-PCR.

The pellets are viruses, and thus, they are incredibly small.  So small that, for all intents and purposes, they are invisible. Creating viral concentrates with invisible viruses was probably the most nerve-wrecking thing I’ve had to do since finals.  Scratch that- it was definitely the most nerve-wrecking thing I’ve had to do since finals.  You have to have a great amount of faith in the fact that you’ve followed procedures correctly, and that the viruses are, in fact, there.  That kind of faith is hard to muster.  But muster it I did, and all of my VCs this summer did actually have viruses in them.

The next post will deal with abundance calculations.