Gram staining is an example of?

If you’re a microbiology nerd like me, then you’ve undoubtedly heard about the miracle technique known as Gram staining. But what exactly does it entail? And why is it so gosh darn important? Let’s dive into this bacterial masterpiece and find out why we should all be thanking Mr. Hans Christian Gram every day.

The basics of Gram Staining

Before we get into the nitty-gritty details, let’s cover some basic facts about this famed process. First off, who even was Mr.Gram anyway? Well, he was a Danish bacteriologist who lived from 1853-1938 (I bet his friends called him “Hank” for short). It was in 1884 that he stumbled upon something big while studying lung tissue under a microscope. He noticed that certain bacteria retained dye when washed with alcohol after being stained purple (we’ll get to these colors later), while others did not retain the color at all! This led him to develop his now-famous ‘stain’ which separates bacteria according to their cell wall composition.

Essentially, gram staining allows us to figure out what types of bacteria are present in a sample by identifying whether they have thick or thin walls made of peptidoglycan – but more on that later. Now let’s see how this whole shebang goes down step-by-step

1) Heat fix your slide – Stick cells onto glass slide with flame

2) Add crystal violet – make everything purple! Simple enough.

3) Rinse & add Lugol’s iodine solution – locks in the color

4)Wash w ethanol till run clear You wanna rinse sure all unwanted impurities go bye-bye

5) Add Safranin counter stain – naughty cells won’t take up pigment and look red instead

6) Blot dry and view under microscope – Stained cells will either show up purple which are Gram-positive or red, which indicates Gram-negative bacteria.

VOILA! now you’ve revealed the identity of suspicious bacterial culprits!

What makes a gram positive bacteria?

So why do some cells turn purple and others turn pink? Well, it all has to do with their structural makeup. Let’s start with the gram-positive fellas first since they’re notoriously more interesting (I’m kidding, please don’t hurt me)

Gram-positive bacteria have thick walls made primarily of peptidoglycan meshwork that can absorb the crystal violet-iodine complex tightly. Why does this happen? Well as we said earlier,Iodine acts like glue linking dye so in gram positive cages glue is stronger aka I-V compex doesn’t wash out during decolorization step making them appear deep stained purple under microscope

Ergo… if your cell stain REAL DEEP PURPLE then it’s likely a little guy carrying around this thick coated armor called “peptidoglycan” – an incredibly strong and dense material around its individual single cell membrane.


Wow! Look at those purples studs sticking out protecting our lil’ friends from outside harm – thanks for making me feel inferior tiny bacterium!

Gram Positive Examples: Streptococcus & Staphylococcus

Marking on The Measure Stick: Ranking Bacteria

You may be wondering what other types of information we can glean from a simple staining process besides these majestic coats of color. In particular, one important application lies not in knowing whether there are gram-negative or gram-positive baddies present but rather the relative amount between the two such groups

By simply observing how much of each type of cell is present we can predict important things about the microbiome, including possible disease states ( if there are lots more gram-negatives.

This technique could be likened to measuring your pee levels on a multi-colored urine test strip (who knew Pepto Bismol-coloured pee meant too much protein), just replace colors with bacteria types and voila! Results in seconds.

Here’s a table outlining the differences between Gram-positive and Gram-negative bacteria:

Color under microscope Wall thickness Outer membrane present Percentages in normal conditions
Gram+ Deep purple Thick Glue like substance called peptidoglycan About 60-70%

Why We LAUD Gram Staining!

Why do we care so darn much about this glamorous staining process anyway? Well, without it our understanding of microbiology would practically be stuck in the stone age. Thanks to Mr.Gram ,we are able to differentiate between countless different species of both pathogenic or beneficial bacteria simply by looking at their physical appearances!

From identifying infections that require antimicrobial treatment and diagnosis for Urinary tract Infections (using urinalysis)to industrial applications like fermentation – It all wouldn’t have been made possible without dear old Hank Christian himself !

Thanks Gram…. I’ll forever have you carved on my next petri dish !


Hank Christian gram: The reason we all love binging T.V. shows while in quarantine!

So there you have it, folks – Gram Staining is an essential tool used almost every day by research scientists, health professionals and industrialists to better understand the world around us & its bacterial inhabitants!

Throwin’ It Back To 1884 : Timeline

  • Invention by Hans Christian Gram in Danish.

  • Theory of Electrical Charges Based on Plant Cell Wall-tissue Chemistry By Emil Fries (limited acknowledgement) published

  • Procedure modified to include decolorization step after failed cure of streptococcus pneumoniae patient.

  • Discovery that perhydrol instead ethanol for washing slide improved stain quality.

Unleashed Albert George Baumann -Helping soldiers with staining kits!

Dr.Albert George Baumann played a key role during World War II as he discovered the potential use of Fortuitum bacteria in finding a powerful antibiotic agent for treating infections among wounded U.S. troops.So, He distributed his own special gram-staining kits he invented to hospital labs under direction from Surgeon GeneralThomas Parran Jr., saving countless lives throughout our history.

And that friends… is how we got rid of Gonorrhoea

ending joke

Looks like dream-granting was one thing they didn’t add bout these legendary inventions 😉

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