No More Blind Dates with Your Bacteria!

Imagine you are a scientist and you have some bacterial growth on a plate. You work with this bacteria and you form what you think is a bond with it because you are a scientist and sometimes scientists are delusional.

So you're working with this bacteria and it behaves a certain way on the plate, but you have no idea what your bacteria looks like individually. You don't know the shape or how big it is or any individual fact about it because it grows in colonies.

Well do I have the procedure for you! This procedure will help you view your bacteria under a microscope and figure out what it looks like! It may even make you more delusional and form a better "bond" with your bacteria because now you will know what it looks like.

This procedure is none other than Gram staining!

Gram staining is a simple procedure that uses stains, decolorizers, and counterstains to let you associate a color - purple or pink - with the type of bacteria you have, as well as see the shape of your bacteria.

The steps are as follows:

• Add a drop of water onto a slide

• Flame an inoculating loop until it glows red

• Let it cool

• Pick a colony and smear it onto the water

• Wait for the water to evaporate, then heat fix by swiping slide through the flame 3x

• Add a few drops of crystal violet

• Wait 60s and then wash off with distilled water

• Add a few drops of Gram's iodine

• Wait 60s then wash off with distilled water

• Drip ethanol on the slide until it runs clear, or until 10 seconds has passed

• Rinse with distilled water

• Add a few drops of safranin

• Wait 60s then wash off with distilled water.

• Pat dry with bibulous paper then view under a microscope

  
  

Now you're ready to view!

• Place dry slide onto the microscope stage

• Make sure the light is turned on and the magnification is set to 10x lens

• Focus the microscope so the bacteria are clearly seen

• Then add a drop of immersion oil onto the slide and switch the magnification setting to the 100x lens

• Re-focus and identify your bacteria

• Move the magnification setting back down to 10x

• Wipe off the 100x lens

When you view your bacteria under a microscope, you will have the chance to see if the bacteria are gram positive or gram negative, as well as their shape. The difference between gram positive and gram negative lies in the peptidoglycan layers of the cell walls, where gram positive bacteria have thick peptidoglycan layers and appear purple, and gram negative bacteria have thin peptidoglycan layers, and appear pink.

Additionally, you might see different shapes in your sample. These different shapes are the actual shape of your bacteria. If you see little circles, or rods, or spiral-shapes, these are all common shapes of bacteria. Multiple shapes in one sample can show either contamination or show some weird bacteria. Some bacteria are a combination of shapes, and they can make the Gram staining results confusing or inconclusive.

Although Gram staining isn't a perfect technique, as it can give weird results if the steps weren't followed properly, or might show inconclusive results based on the type of bacteria, it is generally a good and quick way of telling what your little bacteria friends look like so you can form deeper attachments to them.