Thursday, September 29, 2011

Indentifying Bacteria: Capsule Stain Test

Today, we prepared a capsule stain in order to determine if bacteria 'L' has a capsule. First, we created a stain with Nigrosin by placing a drop on a corner of the slide. Then, we dropped a dollop of our bacteria 'L'into the Nigrosin using an inoculating loop and the aseptic technique. After mixing the two together, we took a clean slide and held it at a 45 degree angle and spread the drop across the surface of the slide, creating a thin, even smear. After some air drying, we were reading to begin the capsule stain. Then we used Crystal Violet to cover the smear  for 1 minute and than rinsed the slide (although not for too long as we did not want to rinse away 'L'). The slide than recieved careful blotting with Bibulous paper. It was than viewed under a microscope at 400x with immersion oil (prevents refraction of light as explained in previous posts!).

Bacteria 'L' & my throat sample (environmental) was found not to have a capsule. There was no transparent matter surrounding the bacteria in a 'halo' as our lab manual refers to it.

Myself holding the spread slide (Nigrosin & 'L' mixture)
Until next lab!
Annie B

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