Hans Christian Gram

Hans Christian Gram
Hans Christian Gram by Hansen & Weller
Born	Hans Christian Joachim Gram (1853-09-13)13 September 1853 Copenhagen, Denmark
Died	14 November 1938(1938-11-14) (aged 85) Copenhagen, Denmark
Known for	Inventing the Gram stain
Scientific career
Fields	Bacteriology
Doctoral advisor	Japetus Steenstrup

Hans Christian Joachim Gram (13 September 1853 – 14 November 1938) was a Danish bacteriologist noted for his development of the Gram stain, still a standard technique to classify bacteria and make them more visible under a microscope.

YouTube Encyclopedic

1/3
Views:
142 337
2 757
124 812

Transcription

Gram Staining The gram stain is one of the most useful methods in identifying bacteria. It is an example for differential staining technique. In this procedure, the bacteria is stained and examined under the microscope. Gram stain permits the separation of all bacteria into two large groups, those which retain the primary dye (gram-positive) and those that take the colour of the counter stain (gram-negative). Procedure: Heat the inoculation loop with burner. Start burning the loop horizontally from its base to vertical position till it becomes red hot. Touch an isolated colony with inoculating loop and swirl it in the drop of water on the slide. If it is broth culture, a loopful of culture can be placed directly on a clean microscopic slide. Now,let the smear air dry at room temperature Now, fix the smear using heat by waving the slide over a flame and be careful not to overheat. Flood the slide with crystal violet, and let stand for one minute. Wash the slide briefly with cold water. Flood the slide with gram's iodine; let stand for one minute; wash off with water. Decolorize until the water flows colourlessly from the slide. Now, flood the slide with safranine; let stand for 30 seconds; wash off with water. Blot the slide dry with bilbous paper. Examine the slide under the microscope for gram reaction in 100X oil-immersion objective lens. We can observe that Gram positive organisms appear purple in colour, while gram negative organisms appear pink in colour. Tips: Only perform gramstains on fresh cultures or log phase culture after 24 hour incubation. Be sure to stop the application of decolourizer immediately after it runs clear to avoid over-decolorizing.

Early life and education

Gram was the son of Frederik Terkel Julius Gram, a professor of jurisprudence, and Louise Christiane Roulund.

He studied at the University of Copenhagen, and was an assistant for botany to the zoologist Japetus Steenstrup. His study of plants introduced him to the basics of pharmacology and the use of the microscope.

Gram began medical school in 1878 and graduated in 1883. He traveled throughout Europe between 1878 and 1885.

Career

Gram stain

In Berlin, in 1884, Gram developed a method for distinguishing between two major classes of bacteria.^[1] This technique, known as Gram staining, continues to be a standard procedure of medical microbiology. This work gained Gram an international reputation. The staining method later played a major role in classifying bacteria. Gram was a modest man, and in his initial publication he remarked, "I have therefore published the method, although I am aware that as yet it is very defective and imperfect; but it is hoped that also in the hands of other investigators it will turn out to be useful."

A Gram stain is made using a primary stain of crystal violet and a counterstain of safranin. Bacteria that turn purple when stained are termed 'Gram-positive', while those that turn red when counterstained are termed 'Gram-negative'.

Other work

Gram's initial work concerned the study of human red blood cells. He was among the first to recognise that macrocytes were characteristic of pernicious anaemia.

During 1891, Gram taught pharmacology, and later that year was appointed professor at the University of Copenhagen. In 1900, he resigned his professorship of pharmacology to become professor of medicine.^[2] As a professor, he published four volumes of clinical lectures which became used widely in Denmark. He retired from the University of Copenhagen in 1923, and died in 1938.^[2]

Popular recognition

On 13 September 2019, Google commemorated the anniversary of his birth with a Doodle for Canada, Peru, Argentina, Australia, New Zealand, Israel, India and some European countries.^[3]^[4]

Personal life

Gram's great-granddaughter Lone Gram is a microbiologist who works at the Technical University of Denmark.^[5]

References

^ Gram, H.C. (1884). "Über die isolierte Färbung der Schizomyceten in Schnitt- und Trockenpräparaten". Fortschritte der Medizin (in German). 2: 185–189.
An English translation is in Brock, T.D. (1999). Milestones in Microbiology 1546–1940 (2 ed.). ASM Press. pp. 215–218. ISBN 1-55581-142-6.
A translation is also at Brock, T.D. "Pioneers in Medical Laboratory Science: Christian Gram 1884". Hoslink. Retrieved 27 July 2010.
^ ^a ^b Jay Hardy. "Gram's Serendipitous Stain" (PDF). Retrieved 13 March 2016.
^ "Hans Christian Gram's 166th Birthday". Google.com. 13 September 2019. Retrieved 13 September 2019.
^ Michallon, Clémence (13 September 2019). "Who was Hans Christian Gram and what did the groundbreaking scientist discover?". Independent UK. Archived from the original on 9 May 2022. Retrieved 13 September 2019.
^ Shekhar, Akarsh (22 October 2020). "Hans Christian Gram: 8 Facts About The Man Who Invented the Famous 'Stain Technique'". DailyHawker. Retrieved 15 January 2022.