Nobel Prize

Discovery of Phagocytosis

Taylor McLelland and Andrea Occhiuti

QualificationsMy name is Ilya Ilyich Mechnikov

and I was born on May 16, 1845 in a small village near Kharkoff in Russia. I went to the University of Kharkoff and studied natural sciences. I was so intrigued with the study of sciences, that I was able to complete four year courses in only two years, earning my degree in natural sciences.

At 20 years old I traveled to Giessen and worked in a laboratory. It was there that I made my first discovery on intracellular digestion in 1865.

Qualifications cont.

In 1867 I taught at the University of Odessa as Professor of Zoology and Comparative Anatomy.

I also studied embryonic development of the cuttle-fish Sepiola and the Crustacean Nelalia. I further studied embryonic development in Messina, which is where I discovered the phenomenon of phagocytosis in 1882.

Leading up to the experiment

Mechnikov and I were studying ways starfish and sponges digest food, when we noticed cells that move from place to place throughout the carcass. They moved by sticking out one part of themselves and then dragging the rest of themselves after that part. We called them wandering cells and wanted to learn more about them.

Experiment

• First, little particles of carmine were placed inside of the larva of a starfish.

• The larvae of starfish are transparent, so it was easy to see what was going on while looking through a microscope lens.

• Once everything was set, it was seen that inside the larva, the cells were slowly moving towards the carmine and then devoured them.

What is Phagocytosis?• Phagocytosis was named after the Greek

word meaning "devouring cells"• Phagocytosis is the process the human body

uses to destroy dead or foreign cells• There are two main types of phagocytic cells

that carry out the process of phagocytosis: Neutrophils

Macrophage

Phagocytosis cont.

• The phagocyte comes into contact with a micro-organism by opsonins. The phagocytes are affected by opsonins which make the micro-organisms stick to the surface of the phagocytic cell.

• Once the micro-organism sticks to the phagocyte, it triggers a phagocyte to throw 'arms' (the real name of these 'arms' is pseudopodia) around the micro-organism, trapping it and enclosing the micro-organism within its membrane.

Phagocytosis cont.

• The membrane surrounding the micro-organism fuses with the membrane surrounding the lysosomes in the cytoplasm of the phagocyte.

• The bactericidal enzymes and other toxic molecules found within the lysosomes then kill and digest the micro-organisms inside a phagocytic vacuole. Then the phagocyte expels all parts of the ingested micro-organism which it cannot use.

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__phagocytosis.html