Professor Denison, who retired in 2018, joined the department in 1992 and advanced to professor in 1997. He served as a researcher in the UC Davis SRP, funded by National Institute of Environmental Health Sciences (NIEHS), for more than 25 years.
Over a 44-year period, Denison focused his research on understanding the molecular mechanisms by which a protein known as the Ah receptor mediates the biological/toxicological actions of dioxins and related chemicals. He was widely acclaimed for his development of the Chemical Activated LUciferase gene eXpression (CALUX) assay, a cell-based bioassay used to detect specific environmental contaminants, including, but not limited, to dioxin-like chemicals and environmental hormones (endocrine disruptors).
The test, approved by the intergovernmental Organization of Economic Cooperation and the U.S. Department of Environmental Protection Agency, is the international standard for detecting environmental contaminants in the protection of human health. Denison also made other seminal contributions to the Ah receptor field and was a leader in advancing the study of Ah receptor biology, said UC Davis distinguished professor Bruce Hammock, the founding director of UC Davis SRP and a close friend and colleague of Denison's.
“He is best possibly known for his fundamental work on the mechanism of action of TCDD and the translation of this knowledge into a quantitative, rapid and inexpensive assays for tetrachlorodioxin like chemicals and other chemicals that bound to the aryl hydrocarbon hydroxylase receptor," Hammock said. "He went on to use the CALUX format to measure a number of other small molecule receptor interactions. Mike was also funded for much of his career by competitive grants from NIEHS, including his MS and PhD work.”
Robert Rice, professor and chair of the Department of Environmental Toxicology, said that "Mike's absence leaves quite a void in our department. Even in retirement, he continued to be a source of wisdom and amusement, and he was still an inspiration to students."
Rice added that he first met Denison in 1992 when he joined the faculty, "and I ended up being department chair in recent years after he declined the position."
Denison, trained in biology, marine biology, animal physiology and environmental toxicology, received his associate of arts degree in biology from the County College of Morris, N.J. in 1975, and his bachelor's degree in marine biology from St. Francis College, Biddeford, Maine, in 1977. He obtained his master's degree in animal physiology from Mississippi State University, Starkville, in 1980, and went on to receive his doctorate in environmental toxicology from Cornell University, Ithaca, N.Y., in 1983. Denison did postdoctoral research at the Department of Clinical Pharmacology, Hospital for Sick Children, Toronto, Canada, from 1983 to 1985, and with Stanford University's Department of Pharmacology, 1985-1988.
Denison began his academic career as an assistant professor in the Department of Biochemistry at Michigan State University, East Lansing, from 1988 to 1992, and then relocated to the UC Davis Department of Environmental Toxicology.
Michael and his twin brother, Steven, were born on Dec. 8, 1954, in Shirley, Mass., the sons of Alan (deceased) and Alma Denison. While the father served in the U.S. Army, the family lived in numerous places around the world and settled in Wharton, N.J. when boys were 11.
“Michael was a happy and optimistic person,” said his widow Grace Bedoian, who retired in 2014 as a UC Davis SRP administrator and a member of the Hammock lab. “The only thing he took seriously was science, which he loved."
“His typical day was spent at work, conducting his research and mentoring students, returning home and making a wonderful dinner at the end of the day, and then retreating to his home office to work until the wee hours of the following morning," she said. "He maintained curiosity and wonder of the world around him. He loved to solve problems and figure out how things worked. He was generous with his friends and colleagues alike and always quick to offer his services to those in need."
Denison is survived by his widow, Grace; his mother, Alma; two brothers (Steven and Daniel) and their wives (Gloria and Angela); two nieces, two nephews, and several grandnephews.
The family thanks the staff at Yolo Cares of Davis for “their exceptional expertise, kindness and compassion in providing in-home hospice care for Michael. All of the staff members at Yolo Cares are truly angels on this earth.” In lieu of flowers, donations may be made to Yolo Cares by contacting (530) 758-5566 or http://www.yolocares.org.
Donations also may be made to the Michael S. Denison, Ph.D. '83 Environmental Toxicology Research Fund, an endowment created at Cornell University by a colleague. Checks payable to Cornell University may be mailed to Cornell University, Box 37334, Boone, IA 50037-0334. In the memo field or in the correspondence, donors are asked to add: Michael S. Denison, Ph.D. '83 Environmental Toxicology Research Fund #0018594. Online gifts can be made at https://giving.cornell.edu/, notating Michael S. Denison, Ph.D. '83 Environmental Toxicology Research Fund #0018594 on the online giving form. ChristyAgnese, director of development in the College of Agriculture and Life Sciences, Cornell University, may be contacted at (607) 279-6884 for further assistance.