Category Archives: Techniques

Tiny particles with big consequences: The number of viruses it takes to start an infection

 

Hepatitis virions, of an unknown strain of the...
Hepatitis virions (Photo credit: Microbe World)

My last post was written to introduce the concept of quasispecies in an RNA virus population.

This article will further expand on the topic and show how the quasispecies concept was used with powerful genetic sequencing technology to figure out a specific question: How many hepatitis C virus particles does it take to start an infection in humans? Continue reading

West Nile Virus in HEK cells

Immunofluorescent Microscopy

West Nile Virus in HEK cells 24 hours post infection, 10x magnification. Green is a FITC label on a cytoskeleton marker and red is Cy3 labeling of West Nile Virus. Note viral exclusion from the nucleus. Image by KD Shives.

Today is exciting because I get to do two things.

1: Post the first successful images of West Nile virus infectined cells that I took on my own and

2: Give a basic explanation one of the most visually impressive techniques at our disposal: immunofluorescent microscopy.

For those of you not familiar with fluorescent microscopy this is a very basic image taken with only two fluorophores, or dyes, to color the image. In this image the green color is from FITC and the red comes from Cy3.

So how is it that I can make images that look like this? How do you target the dye to only one part of the cell? Why is all of the cell green and only some parts are red? What is the yellow? Read on for the answers… Continue reading

Ask A Microbiologist #1

Work. (1 of 2)
Work. (1 of 2) (Photo credit: musicalwds)

After writing for a month I’ve gotten my first reader question and I’m excited to share the answer with the rest of you. Here’s the question I got a week ago from a reader working in a tissue bank regarding their samples:

I work in a tissue bank and have some concerns in the practice we use for handling our tissue. When the tissue is ready for processing we receive it in a partially frozen state. To thaw, we have the tissue soak in sterile water for a period of 15 min. We process in rooms with air exchanges that are similar to a hospitals OR. We do have preventative measures after the process we take to protect the tissue. However, we recently have been trying to accommodate clients by processing aseptically. My question is, can the use of water create a harbor for bacterial growth considering the length of time the tissue will remain in the room throughout the duration of the process. (8 to 16 hours) and would there be any alternative means of a safer way in which to thaw the tissue?                                                                                                                -G

 This is a great question but a little bit outside of lab work that I’m personally familiar with. Thankfully though, aseptic technique works the same way everywhere, so here are some suggestions I came up with based on my experience. Continue reading

Cell Culture Dish

How do viruses move outside the cell?

In line with the recent article “Are viruses alive?” I would like to further explore the general nature of viruses. One question that I was recently asked was “does a virus move?” Being that viruses are not technically alive in the sense that we know it they also cannot move in a self-directed manner. This is in stark comparison to some other microbes such as Schistosoma cercariae, a parasitic worm, which is capable of burrowing through intact human skin and gaining access to the vascular system within 5 minutes (1). Thankfully viruses cannot do this, much to our benefit. Because of their very nature viruses cannot mechanically move in a self-directed manner and are subject to movement solely based upon environmental interactions. Essentially, they are not only hijackers who take over cellular processes for their own good, but environmental hitchhikers as well. Continue reading