Day 6 - Viewing Acid Fast, Capsule, and Endospore Stains

Today, we returned to the scene of the crime. Our mistake of a day yesterday was fixed up and we are good to go. First we looked at the original throat bacteria that we gram stained. This was properly fixed and heated this time. This is what they ended up looking like:

Grace's throat - Gram positive, Cocci

This was deemed to be Gram positive because it held the dark stain of the crystal violet and did not pick up the safranin color. When looked more closely in the view of the microscope, you can see the patches of circular bacteria, making it cocci. 

Next, we took a look at our capsule stains. This type of slide shows that there is a capsule when there is a white glow outline around the bacteria, with the small line of the bacteria on the inside. This is because the stain will hold to anything but the capsule. In our slide, you can see some of the bacteria that have a capsule stain. 

Capsule stain

The acid-fast stain is the next one that we will look at. It will be a positive match for an acid-fast bacteria if it held some of the red color from the carbol-fuschin. This would mean that, even after adding the acid-alcohol, which is a decolorizing agent, it held on to the dye and was not stained with the methylene blue in the end, which is the counterstain. In our bacteria, we found all of the bacteria to be blue, stained with the methlyene blue, proving that our bacteria is not acid-fast. 

Acid-Fast Stain - Negative Result

The last stain that we did was the endospore stain.  A positive result, showing the existence of endospore stain, would be green stain on the slide. The endospore's protein coat on the outside will resist the color of most stains. Malachite green on high heat is on of the only ones that will stick. This slide shows that there is only the pink color. This pink color means that the bacteria held onto the safranin and none of the Malachite green, meaning that there are no endospores in this bacteria.

Endospore - Negative Result

Today in lab, we also looked into the workings of an anoxic jar. This is a jar that will allow for the anaerobic atmosphere that some bacteria grow better in.  The GasPak will generate CO2 and H2. The oxygen in the atmosphere will react with the H2, forming water, and the environment will be anaerobic. The methylene blue indicator strip turns blue with oxygen. This is an indicator to see if the GasPak worked properly. We took streak plates of each of our bacteria, and placed them in the jar. We will return tomorrow and see if our bacteria grows in carbon dioxide as well as oxygen. 

Anoxic Jar

*App of the Day - Some bacteria will only grow in the carbon-dioxide/non-areobic environments. These are call obligate anaerobes. These are the type of bacteria that will only grow in the anoxic jar. An example of this is Prionibacterium acnes. This is the bacteria that causes acne. Because this cannot survive in the oxygenated environment, exfoliating, allowing oxygen to enter your pores, is one of the best ways to get rid of acne.