Lafayette B. Mendel

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Lafayette B. Mendel

Lafayette Benedict Mendel (born February 5, 1872 in Delhi , New York , † December 9, 1935 in New Haven , Connecticut ) was an American biochemist . He studied from 1887 at Yale University , received his doctorate here in 1893 under Russell Henry Chittenden and was from 1903 over thirty years professor of physiological chemistry at the university. At the same time as Elmer McCollum , Mendel and Thomas Burr Osborne published the discovery of vitamin A in 1913. For more than twenty years, both of them jointly and independently of McCollum researched the substances that Frederick Gowland Hopkins called accessory food factors (in other words, ' additional food factors ').

Life

Youth and Studies

Lafayette B. Mendel was born in 1872 to German immigrants in Delhi , New York State . His father Benedict Mendel, born in Aufhausen in 1833 , came to the United States in 1851 and settled in Delhi. His mother Pauline Ullman was born in Eschenau in 1844 and came to the USA in 1870, where she married Benedict Mendel in the same year. Lafayette B. Mendel had a younger brother who died in 1901. He received his education at the State Delaware Academy in Delhi. In 1887 he took the aptitude test for Yale College and also won a state scholarship . In 1891 he was the youngest in his class to graduate with a Bachelor of Arts . He then went to the Sheffield Scientific School at Yale University , where he received his doctorate in physiological chemistry under Russell Henry Chittenden after two years in 1893 .

Professor and Research at Yale University

Lafayette B. Mendel House in New Haven , Connecticut . Mendel lived in the house, built by Henry Austin in 1858, from 1900 to 1924, a National Historic Landmark since 1976 .

After his doctorate he became an assistant in Chittenden's Laboratory of Physiological Chemistry , was between 1895 and 1896 for studies at the University of Breslau and the University of Freiburg, and in 1897 he was assistant professor and in 1903 professor at the Sheffield Scientific School of Yale University. He was appointed Sterling Professor of Physiological Chemistry in 1921 and, after Chittendens' retirement in 1922, became director of the faculty, where he worked for over forty years until his death in 1935. More than 300 students studied under Mendel, 92 of whom did their doctorates with him, including Icie Macy Hoobler and Florence B. Seibert .

In the early years, his research focused on the chemical processes involved in the digestion of proteins , fats and carbohydrates . In 1909 he began a twenty-year collaboration with Thomas Burr Osborne from the Connecticut Agricultural Experiment Station , who mainly dealt with vegetable proteins, in particular with cereal proteins such as gliadin and zein , which are divided into the Osborne fractions named according to their solubility . In animal experiments with albino rats, Osborne and Mendel investigated the influence of different isolated proteins on the growth and development of young animals and on the health of adult rats. The experiments showed that some amino acids are essential for survival and have to be ingested with food, while others are only crucial for the growth of young animals.

Discovery of vitamin A.

The experiments also showed that when young animals were exclusively fed with protein extracts, sugar, starch and pork fat, their growth was restricted, but that they developed fully when milk powder or butter was added. Special protein-free milk powder also led to poor development and comparisons between the normal and protein-free milk powder showed that the latter also lacked milk fat. Osborne and Mendel concluded that in addition to proteins, milk must contain another substance that is essential for growth. This finding finally led to the discovery of the fat-soluble factor A, later called vitamin A , at the same time as Elmer McCollum . McCollum had published the results of similar studies a few months before Osborne and Mendel in 1913 and had come to the same conclusion.

In the following years, Osborne and Mendel extracted a yellowish oil from butter, egg yolk and cod liver that could not be obtained from olive oil or pork fat. In the 1930s, other scientists were able to show that the yellowish dye is β-carotene , a precursor of vitamin A ( retinol ). Until the death of Osborne 1929 investigated a variety of vegetable and animal food products for their content of the fat-soluble Vitamin A, as well as the water-soluble vitamin B .

family

Lafayette B. Mendel married on July 19, 1917 Alice R. Friend, a graduate of the University of Wisconsin , who supported him in his work and with whom he had a happy marriage; they had no children. After a long illness, Mendel died on December 9, 1935. Exhausted from the mental and physical stresses caused by her husband's illness, Alice R. Friend died a few weeks earlier.

Awards

Works (selection)

  • Childhood and Growth. FA Stokes, New York 1905.
  • Changes in the Food Supply and their Relation to Nutrition. Yale University Press, New Haven 1916.
  • Nutrition: the Chemistry of Life. Yale University Press, New Haven 1923.
  • Vitamins; a symposium on the present status of the knowledge of vitamins. American Medical Association, Chicago 1932.

literature

Individual evidence

  1. ^ Russell Henry Chittenden: Biographical Memoir of Lafayette Benedict Mendel, 1872-1935. In: Biographical Memoirs. Vol. XVIII, 1937, pp. 123-155, here pp. 123-125.
  2. ^ William C. Rose: Lafayette Benedict Mendel - An Appreciation. In: The Journal of Nutrition. Vol. 11, No. 6, 1936, pp. 607-613.
  3. ^ Russell Henry Chittenden: Biographical Memoir of Lafayette Benedict Mendel, 1872-1935. In: Biographical Memoirs. Vol. XVIII, 1937, pp. 123-155, here pp. 125-127.
  4. ^ J. Russel Lindsay, Henry J. Baker: Historical Foundations. In: Mark A. Suckow, Steven H. Weisbroth, Craig L. Franklin (Eds.) The Laboratory Rat. 2nd edition, Elsevier Academic Press, 2006, ISBN 978-0-12-074903-4 , pp. 1-52, here pp. 17-19.
  5. ^ A b Russell Henry Chittenden: Biographical Memoir of Lafayette Benedict Mendel, 1872-1935. In: Biographical Memoirs. Vol. XVIII, 1937, pp. 123-155, here pp. 129-135.
  6. ↑ a b George Wolf: A history of vitamin A and retinoids. In: The FASEB Journal. Vol. 10, No. 9, 1996, pp. 1102-1107.
  7. ^ Russell Henry Chittenden: Biographical Memoir of Lafayette Benedict Mendel, 1872-1935. In: Biographical Memoirs. Vol. XVIII, 1937, pp. 123–155, here p. 136.
  8. ^ Lafayette Benedict Mendel. National Academy of Sciences, Deceased Members. Retrieved August 9, 2014.
  9. ↑ Member entry of Lafayette Benedikt Mendel at the German Academy of Natural Scientists Leopoldina , accessed on February 2, 2016.
  10. ^ Gold Medal Award Winners. American Institute of Chemists. Retrieved August 9, 2014.
  11. ^ Book of Members, Chapter M. American Academy of Arts & Sciences, p. 374. Retrieved August 9, 2014.
personal data
SURNAME Mendel, Lafayette B.
ALTERNATIVE NAMES Mendel, Lafayette Benedict
BRIEF DESCRIPTION American biochemist and co-discoverer of vitamin A.
DATE OF BIRTH February 5, 1872
PLACE OF BIRTH Delhi , New York
DATE OF DEATH December 9, 1935
Place of death New Haven , Connecticut