John Howard Mueller

John Howard Mueller (June 13, 1891, Sheffield, Massachusetts – February 14, 1954) was an American biochemist, pathologist, and bacteriologist. He is known as the discoverer of the amino acid methionine in 1921, and as the co-developer, with Jane Hinton, of the eponymous Mueller–Hinton agar. Biography J. Howard Mueller was the son of a Unitarian clergyman and grew up in Illinois. He studied biology at Illinois Wesleyan University with a bachelor's degree in 1912. He was then a chemistry instructor at the University of Louisville for two years before receiving his master's degree in 1914. He became interested in pathology and bacteriology and in 1914 attended a summer course at the Medical Faculty of Columbia University. He stayed there for further studies after receiving a scholarship and received in 1916 his doctorate Ph.D. in pathology. He then became an assistant pathologist at the New York Presbyterian Hospital. In 1917 he was a volunteer at the front in France with a medical unit and was involved in empirical proof of the transmission of trench fever by lice. In 1919 he was discharged as a lieutenant and became an instructor in bacteriology under Hans Zinsser at Columbia University. (The academic position to which Mueller was appointed was formerly held by J. Gardner Hopkins, who was promoted.) At Columbia, Mueller did research on the requirements for the growth of cultures of pathogenic bacteria. He wrote: He was the first to succeed in isolating and characterizing methionine, which certain streptococci needed for their growth. In 1923 when Zinnser was appointed as the chair of the department of bacteriology and immunology at Harvard Medical School, Mueller followed him and became an assistant professor there. However, Mueller had to interrupt his work on bacterial metabolism, including work on Rous sarcoma virus with a dispute over William Ewart Gye's theory. In 1930 Mueller began his studies on the nutritional requirements of the diphtheria bacillus. His work with the diphtheria pathogen was also of practical importance for the development of vaccines against diphtheria (by optimizing the bacterial cultures). From the early 1940s, he turned to research on the tetanus pathogen. After Zinsser's death in 1940, Mueller became head of the bacteriology department at Harvard. He continued to do research.