Tuesday, September 24th 2013

*This blog does not reflect Franciscan University in any way*

Dear Blog and Blog Readers, 

Lab today consisted of viewing our slides that had a negative stain under the oil immersion lens, doing one last gram stain of the red pigmented soil bacteria, and making a completely new petri dish of a bacteriophage. 

First of all, we took the slides that a had negative stain and we made a capsule stain out of them by adding some crystal violet stain to the slide and then rinsing it off indirectly

Max and I staining the negative slides with crystal violet for 20 seconds. 

Rinsing off the crystal violet stain.

These next two images are the unknown (S2) negative capsule stain under the oil immersion lens.

Our conclusion is that there were no capsules. 

These next two images are our environmental sample negative capsule stain under the oil immersion lens.

Our conclusion is that we have spores but no capsules. 

Spores are often found in soil bacteria so it is not surprising that we found them in this sample. Spores allow bacteria to survive under harsh conditions such as extreme heat, light, etc. This allows the bacteria to germinate when it return to conditions that are viable for life. Swelling that is a result from endospore (a spore inside a bacterium) can shed light on the species of bacteria it is. (see bibliography)

Capsules are attached to the cell wall and very organized. They are made of polysaccharides and are used to identify a species of bacteria. Colonies with capsules are usually smooth while those without capsules are rough. This is surprising since we did not have any capsules from our unknown or our environmental sample when both colonies were smooth. (see bibliography)

Here we are making the petri dish with the bacteriophage.

 

Max sampling the bacteria "G"

Max using a wave motion to put the bacteria in a petri dish. 

Max then wrote his initials in the petri dish with a bacteriophage.

We predict that there will be no bacteria that grows where Max wrote his initials because the bacteriophage is a virus and will kill the bacteria where Max wrote his initials. 

Unfortunately our last gram stain did not work out, so we will be finishing that next class!

Bibliography:

Duben-Engelkirk, Janet, EdD, MT(ASCP). "Chapter 3: Cell Structure and Taxonomy."Burton's     Microbiology for the Health Sciences. By Paul G. Engelkirk, PhD, MT(ASCP), SM(AAM). 9th ed. Baltimore: Lippencott Williams & Wilkins, 2011. 32-34. Print.