Marjorie Maxine Nelson

Background

Marjorie Maxine Nelson was born on December 24, 1909 in Kansas City, Missouri, United States. She was the daughter of Aubrey Orville Nelson, a manager for Swift and Company, and of Maude Mintz.

Education

Fascinated by science from an early age, Nelson entered Whitman College in Walla Walla, Washington in 1927, graduating in 1931 with an Bachelor of Arts in chemistry. She then studied organic chemistry at the University of Washington at Seattle, from which she received a master's degree in 1936. She received Doctor of Philosophy degree in 1944.

Career

Nelson's budding interest in chemical problems in biology next took her to the Institute of Experimental Biology (IEB) at the University of California in Berkeley, where in 1938 she became a research assistant to Herbert M. Evans and started her lifelong research on the role of various vitamins in reproduction and development. Nelson remained on the large interdisciplinary research staff of the IEB, first as a research fellow, then as a research associate, and assistant and associate research biochemist. In 1958 the IEB was dismantled and the personnel were divided between the Department of Anatomy and Physiology on the Berkeley campus and the Department of Anatomy at the University of California Medical School in San Francisco. Although Nelson moved her laboratory to San Francisco, she retained the title of lecturer in both departments.

Beginning in 1945, Nelson published a steady stream of more than 100 original research papers.

Much of Nelson's research dealt with the growth, reproduction, and lactation of rats maintained on purified diets. Using rats, she systematically determined the effect on the growth, maturation, and reproduction of nutritional deficiencies in the various B vitamins, protein, and a number of minerals. After eliminating any possible deleterious contributions by the genetic condition of the mother, she carefully cataloged the effects of specific deficiencies on the developing fetus. It was in this area that she made her greatest contribution. In 1950, Nelson discovered marked skeletal abnormalities in the fetuses of rats when the mother was deficient in folic acid, thus confirming and amplifying for another vitamin the already known teratogenic effect of vitamin A deficiency in pregnancy. Later she determined the teratogenic effects of other B vitamin and mineral deficiencies and those of low-protein diets.

In collaboration with H. M. Evans and his associates, Nelson attempted to use the experimental teratologies to pinpoint the biochemical reactions critical for any given step in embryogenesis. Thus, by determining whether certain metabolites, including hormones, could protect the fetus, conclusions could be drawn about the type of proteins or enzymes involved in that step. This is a difficult problem, and this work, although extensive, was not brought to full fruition. But she did show the interrelation between hormonal balance and nutritional requirements.

She was a charter member of the Teratology Society, its secretary-treasurer from 1960 to 1962, and its president-elect when she died in San Francisco.

Achievements

• Nelson was recognized internationally for her many significant contributions to the fields of nutrition, vitamin-hormone interrelationships, reproductive physiology, and teratology. She demonstrated that there are limits to the well-known ability of the maternal organism to deplete itself in order to protect the fetus from the effects of malnutrition, a fact of the greatest importance for undernourished human populations. Most important, she further established that each nutritional factor is needed for a specific critical period in fetal development, and that even the most transitory deficiency can be highly teratogenic if it occurs at a critical time. By feeding rats diets deficient in protein, minerals, or specific vitamins on the corresponding critical days of gestation, Nelson and her associates were able to experimentally produce in rats all types of birth defects known in humans. Her extensive nutritional data, together with data of others on teratogenic effects produced by toxic agents, such as viruses, demonstrated that birth defects were primarily nongenetic, although genetic factors might influence the outcome of exposure to a teratogenic substance.

Personality

Nelson was extremely shy and suffered from a progressive loss of hearing. Despite her handicap, which she largely ignored, she was a lucid lecturer. She was a pedagogue in the best sense of the word. Her greatest ambition and pride was to be a good mentor, a role in which she obviously succeeded. Several of her students went on to head academic departments, a fact that highlights the irony that Nelson herself never had a professorial position.

Throughout her career she did most of her own laboratory work, which required her to be superbly organized, thorough, and persistent.

Connections

She never married.

Father:

Aubrey Orville Nelson

manager

Mother:

Maude Mintz