Recorded: 08 Jun 2006
The first problem was one I was handed sort of on a silver platter when I went to the Mass General Hospital in Boston. I was in the department of medicine at Harvard was located at Mass General Hospital in the Huntington laboratories. The Chief of the laboratory, Dr. Joseph Aub who is a world known physician told me about beryllium and the fact that beryllium was causing very severe illness in women who were working in factories to remove the phosphors from inside fluorescent lamp bulbs. They wanted to retrieve the phosphors. One of the key ingredients in the phosphor was beryllium, the metal beryllium. It’s the lightest metal with an atomic weight of 9.I think that’s right. It’s long time ago.
It caused some interesting effects that the scientists have studied, mainly if injected into rabbits it caused bad bone tumors. If it was injected into—well, these women who were scrubbing out the tubes died, almost all of them of severe pulmonary disease as a result of breathing in the beryllium.
So he said, Mahlon, study the biological effects of beryllium and see what you can find out. That’s all he told me.
There was one person in the laboratory who was doing a little work in this area who helped me get started, but I conceived the idea early on within a month or two of coming to the laboratory to study the effects of beryllium on the growth of plants. In particular the growth of tomato plants which happened to be useful. I did that because magnesium is a central element in the center of the chlorophyll molecule. There was some evidence that beryllium competed with magnesium in biological systems.
So I thought, well maybe beryllium [will] compete with the magnesium in chlorophyll and have some interesting biological effects. I grew tomato plants in the hospital. It didn’t work out very well. I was sort of embarrassed to be growing plants when I should be taking care of patients. So I took them home and grew tomato plants at home. I did most of my early experiments at home and discovered that beryllium does in fact substitute for magnesium in the growth of plants.
That is, if I reduced the magnesium concentration in plants and added beryllium the plants grew much better. If I reduced the magnesium completely and it disappeared, beryllium had a very toxic effect on the plants. This was interesting and to make a long story short, I discovered that there was no replacement of magnesium in chlorophyll by the beryllium. So what I had hoped to find I didn’t find. But I did find this interesting effect of beryllium on the growth of plants and subsequently did a number of other experiments in the next two years that didn’t really reveal very much more about beryllium, but made me convinced that I could think of an idea and carry it out and get some kind of a result even though the result wasn’t very exciting.
Mahlon Hoagland, a molecular biologist who was one of the discoverer of the transfer ribonucleic acid - tRNA. He received a medical degree from Harvard Medical School in 1948. He served as a doctor during the Second World War. When the War ended he returned to Harvard and became researcher in the Huntington Laboratories at the Massachusetts General Hospital in Boston. He worked in the bacteriology and immunology department of Harvard Medical School from 1952 till 1967.
Working together with Paul Zamecnik and Elizabeth Keller he discovered the initial steps of protein synthesis. Two years later in 1958 Hoagland and Zemecnik discovered tRNA. His main input to the laboratory was in his work with amino acid activating enzymes. He noticed that certain enzymes were required to activate amino acids so they could combine with tRNA molecules and eventually be incorporated into new protein molecules. These enzymes were named aminoacyl tRNA synthetases.
In 1957 Hoagland moved to Cambridge where he worked for a year with Crick at Cambridge University. Working together they tried to explain the genetic code.
He was Associate Professor of Microbiology at Harvard Medical School and in 1967 was appointed professor in the biochemistry department at the Dartmouth Medical School. After 3 years he left Dartmouth and became Director and President of the Worcester Foundation for Experimental Biology in Massachusetts. He retired in 1985.
Mahlon Hoagland was awarded the Franklin Medal for life science. He was a member of the American Academy of Arts and Sciences and the US National Academy of Sciences. He died on September 19, 2009.
More Information: Wikipedia