Google celebrates legendary microbiologist Hans Christian Gram turning 166 in today's Doodle

One of Gram's inventions is a mainstay in microbiology: the Gram-staining technique used world-over to identify bacteria.


Today's Google Doodle celebrates Danish microbiologist Hans Christian Gram's 166th birthday with depictions of Gram surrounded by some of his most important work over the years till his demise on 4 November 1938. The Doodle was illustrated by Mikkel Sommer, a guest artist from Denmark.

One of the most important of Gram's inventions is a mainstay in microbiology: the Gram-staining technique used world-over to identify bacteria. Scientists, doctors and medical technicians still use this method to identify and classify bacteria into different types. Gram was drawn to natural science early in life, earning a B.A. at the Copenhagen Metropolitan School in Copenhagen, Denmark. He also worked as a research assistant in botany at the local zoo, which cultivated his interested in medicine. Gram went on to earn his M.D. in 1878 from the University of Copenhagen.

Google celebrates legendary microbiologist Hans Christian Gram turning 166 in todays Doodle

Today's Gram-Doodle. Image: Screengrab from Google.com

After years of holding several assistant positions in Copenhagen hospitals, he authored an award-winning essay on the size and number of human erythrocytes (red blood cells) in patients with chlorosis, a.k.a "green sickness", which gave them a distinct skin green tinge. He went to defend his thesis the following year — an elaborate report on the size of red blood cells.

He traveled throughout Europe soon after, studying bacteriology and pharmacology. His travels eventually led him to the lab of Karl Friedländer, a German microbiologist. It was here that Gram discovered that treating bacteria with a cocktail of crystal violet stain, iodine solution, and organic solvent would reveal key structural differences in different bacterial samples. Cells that were considered to be "Gram-positive" have an abundance of a specific polymer (peptidoglycan) and few lipids (a distinct fat/oil biomolecule found in all living cells), unlike bacteria that are "Gram-negative".

Gram staining can help tell types of bacteria apart. Image credit: thisonevsthatone

Gram staining can help tell types of bacteria apart. Image credit: thisonevsthatone

A gram-positive bacteria would appear purple when looked at under a microscope, but the stain in a Gram-negative bacteria would simply be washed away, with very few peptidoglycan polymers for the stain to hold on to. The Gram staining technique has single-handedly helped diagnose countless bacterial infections — notably, Streptococcus pneumococci, a Gram-positive bacterial pathogen that causes a variety of life-threatening illnesses.

The modest Danish microbiologist published his findings in a scientific journal in 1884, where he wrote, "I have therefore published the method, although I am aware that as yet it is very defective and imperfect; but it is hoped that in the hands of other investigators it will turn out to be useful."

Little did Gram know it would be the first lesson taught in Microbiology 101 in every school and university, over a hundred years later.

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