Lecture Notes: Misha's Discovery of DNA

Introduction

• Misha was tasked with studying the chemistry of white blood cells at the castle.
• Focused on the large nucleus at the center of the cell.
• Needed two key things for his research: a supply of cells and a method to isolate the nucleus.

Collection of White Blood Cells

• Tubigan was an ideal location due to the ongoing war with Prussia.
• Injured soldiers had infected wounds producing pus, which is rich in white blood cells.
• Misha collected old bandages from these soldiers to scrape off the pus.

Use of Pepsin

• Misha needed another component: pepsin, found in the mucus lining a pig's stomach.
• Went to a local slaughterhouse to obtain a pig's stomach.
• Pepsin is an enzyme that helps break down and digest food.
• Misha collected the stomach mucus for pepsin.

Conducting the Experiment

• Misha carried the bandages and pig's stomach back to the lab.
• Experiment steps:
  1. Scrape pus from the bandages (representative material: mayonnaise).
  2. Wash the pepsin out of the pig’s stomach using an acid.
  3. Mix the extracted pepsin with the pus to break down white blood cells.
  4. Analyze the isolated nuclei.

Discovery of Nucleon (DNA)

• Misha analyzed the nucleus and discovered a strange molecule containing carbon, hydrogen, oxygen, nitrogen, and phosphorus.
• Named the new molecule 'nucleon,' now known as DNA.
• Repeated experiments using sperm cells from various animals (frogs, carp, bulls, salmon).
• Consistently found the same molecule each time.

Historical Significance

• Some of Misha’s original DNA extractions have survived.
• Example: DNA from salmon sperm extracted in the 1870s.
• Marked the beginning of a scientific revolution in understanding genetic material.