Johann Friedreich Miescher, II Biography

DNA is now a household word, but its existence was unknown until 1869. During that year, Johann Friedreich Miescher II first isolated DNA from cells. Born in Basel, Switzerland in 1844, he was the son and nephew of distinguished anatomists at the University of Basel. Miescher himself studied medicine at the University, but decided to study chemistry instead because he was concerned that his partial deafness, caused by an earlier bout with typhus, would impair his ability as a physician.

Miescher became a student of Felix Hoppe-Seyler, whose laboratory was located in the castle of Tubingen, Germany. In 1869, Miescher collected the dressings of wounded soldiers and scraped the pus off the dressings. From the white blood cells in the pus he isolated the nuclei from the cytoplasm; and from the nuclei, he extracted a substance that contained phosphorus in addition to the carbon, hydrogen, oxygen, and nitrogen typically found in organic molecules. Miwscher determined that this material was not protein because it was unaffected by the action of pepsin. He called the material "nuclein." Only after 1889 was nuclein called nucleic acid.

The discovery of nuclein astonished Hoppe-Seyler, who had previously discovered the substance lecithin. Up to that point, lecithin was the only natural substance known to contain both phosphorus and nitrogen. Hoppe-Seyler wouldn't allow Miescher to publish his work for two years, because he wanted to investigate nuclein himself. He was able to extract nuclein from yeast cells.

In 1855, Miescher founded Switzerland's first physiological institute. Apart from his discovery of nucleic acids, he is also credited with the discovery that the rate of breathing is determined, using a feedback mechanism, by the concentration of carbon dioxide in the blood.

Miescher also continued his work on nuclein extracted from salmon sperm. He was interested in the chemical agent of fertilization, and said in 1874, "If one wants to assume that a single substance...is the specific cause of fertilization than one should undoubtedly first of all think of nuclein." Eighty years later, Watson and Crick would prove his hunch to be correct, but Miescher did not follow it up himself. Albrecht Kossle, a later student of Hoppe-Seyler, analyzed the chemical content of nuclein in detail, and in 1910, was awarded the Nobel Prize in medicine or physiology for his work on proteins and nucleic acids.

When Miescher became ill from tuberculosis, he required treatment in a sanatorium. Ever the scientist, he took advantage of the opportunity to study the effects of high altitude on the makeup of blood. He observed that the count of erythrocytes increased with the altitude. Mistier died of tuberculosis in Davis, Switzerland, in 1895. Mistier is honored today by the Fried Reich Mistier Institute in Basel, and the Fried Reich Mistier Laboratory of the Max Planck Society in Tubing.