Are you (ab)staining from (fast) acid?

Fellow bloggers;

This week in lab we used certain techniques to determine if our soil microbe along with another sample bacteria was an acid-fast or non-acid fast organism. An acid- fast organism contains a waxy-like cell wall, that with the techniques used, will turn a certain color to determine if the organism is acid-fast or non-acid fast. The primary stain used works by penetrating and sticks to the cell wall turning the organism blue (non-acid fast) or purple (acid-fast). An acid-fast microorganism has a cell wall with a high lipid content that allows the wall to bind to carbol-fuchsin (discussed later). Acid-fast microbes belong to the genus of Nocardia spp. or Mycobacterium spp.

Our methods included transferring our microbe to a microscope slide and flooding the microbe with carbol-fuchsin and methylene blue. These are two major dyes that are used in acid-fast staining techniques. Once we created the slides, we used oil immersion to increase the resolution on the micro scope. The first slide we looked at was our control microbe that we had saved from our soil sample.

This is our control microbe from our soil sample, which turned out to be non-acid fast due to the blue color of the microbes. Through the dichotomous key provided, I believe this sample is from the genus of listeria monocytogenes bacteria due to the overall shape, as well as the bacteria being non-acid fast. Also, this bacteria was characterized this way because of the very small, circular shape which looks similar to the genus of listeria monocytogenes.
                                         

This was our second microbe that we tested in the experiment, which also turned out to be non-acid fast. This was determined due to the blue coloring of the organism. This bacteria was from a sample of B. subtius , which turned out to have strains of bacteria unlike our first microbe tested. I believe this microbe is from the Actinomyces spp. due to the long strain-like structure seen in this picture.

 

There are a few conflicts in this blog due to the lack of tests that haven't been run yet. Although these are all educated guesses on which are based off of a dichotomous key, this week in lab will help us further investigate which genus our microbe belongs to with determining whether it is catalase positive or catalase negative. This will help us in the future to really narrow down which microbe we have been working with in lab.

 

See you next week,

M&M Microbiology