Masters Theses


"The relationship between energy expenditure and longevity is a long standing question in aging studies. The empirical results have contradictory effects on the existing theories. A theoretical model and an experimental test of it were presented, revealing the detailed tradeoffs between metabolic rate, biosynthetic rate and cellular damage level. The dissipative mechanisms of oxidative metabolism cause various forms of cellular damages. To counteract the accumulation of damage, organisms have evolved highly efficient maintenance mechanisms. If there is no other energy demand possess, then most of the cellular damage would be repaired, regardless of how metabolic rate varies. However, the repairing mechanisms cost energy. When the energy that could be allocated to repairing is otherwise channeled to biosynthesis during growth, the damage is inevitably accumulated, despite the high repairing efficiency and the variation in biosynthetic rate, and will have a significant impact on the cellular damage level. The model predicts that cellular damage is more sensitive to biosynthetic rate than metabolic rate. To test the prediction, a broad variation in the metabolic and biosynthetic rate was induced in 5th instar hornworms, and assayed the corresponding lipid peroxidation as an indication of cellular damage. The results showed that the metabolic rate had a negligible effect on lipid peroxidation, and the biosynthetic rate had increased the peroxidation. Our study answers a long-standing question regarding the oxidative stress theory of aging: that the treatments that vary the metabolic rate but fail to change the biosynthetic rate have no effects on cellular damage or lifespan, whereas the treatments that change the biosynthetic rate but keep the metabolic rate unchanged will vary animal life span"--Abstract, page iv.


Hou, Chen

Committee Member(s)

Huang, Yue-Wern
Olbricht, Gayla R.


Biological Sciences

Degree Name

M.S. in Applied and Environmental Biology


Missouri University of Science and Technology

Publication Date

Fall 2015

Journal article titles appearing in thesis/dissertation

Cellular oxidative damage is more sensitive to variation in biosynthetic rate than in metabolic rate: A test of the theory on hornworms


x, 69 pages

Note about bibliography

Includes bibliographical references (pages 58-68).


© 2015 Palihawadana Walauwe Kamalika Kaushalya Amunugama, All rights reserved.

Document Type

Thesis - Open Access

File Type




Thesis Number

T 11196

Print OCLC #


Electronic OCLC #


Included in

Biology Commons