Thesis (Ph. D.)--University of Chicago, Committee on Immunology, August 2000. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 251-269) Also available online.

Thesis (doctoral)--University of Stockholm, 1983. / Added t.p. laid in. Includes bibliographical references.

Thesis (Ph. D.)--University of Oregon, 2006. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 63-68). Also available for download via the World Wide Web; free to University of Oregon users.

published_or_final_version / Medicine / Doctoral / Doctor of Philosophy

Mitochondria were extracted from seedling radicles of Pima S-5 and Pima E-14 cottons and the state 3 respiration, state 4 respiration, ADP:O ratio and respiratory control (RC) ratio were measured in vitro over a range of temperatures from 6 to 18C. Mitochondria from E-14 seedlings exhibited a mean state 3 respiration rate of 13.42 μMO₂/min/gm tissue while mitochondria from S-5 seedlings showed a mean state 3 rate of 17.94 μMO₂/min/gm tissue. Mean state 4 respiration exhibited a similar trend with measurements of 73.4 μMO₂/min/gm tissue and 11.73 μMO₂/min/gm tissue for E-14 and S-5. Mitochondria from E-14 seedlings exhibited a mean ADP:O ratio of 3.73 compared to an ADP:O of 3.28 for S-5, across all assay temperatures. Mean respiratory control ratio was 1.79 for E-14 and 1.53 for S-5. These lower respiration rates of E-14 coupled with higher ADP:O ratios and RC ratios support a greater respiratory efficiency at low temperatures of this variety compared to S-5. Additionally, the E-14 mitochondrial membranes exhibited an ability to remain in a fluid state to a lower temperature than Pima S-5 mitochondrial membranes as judged by Arrhenius plots of respiration. Since mitochondrial respiration is considered to be regulated by membrane-bound enzymes, any change in membrane fluidity would conceivably affect mitochondrial enzyme activity and thus alter respiration rates. Changes in respiration rates will be reflected as a break in an Arrhenius plot. The mean break point temperature of state 3 respiration was 10.7C for E-14 and 13.4C for S-5. The mean break point temperature for state 4 respiration was 10.9C for E-14 and 13.6C for S-5. The ability of E-14 to withstand a greater degree of chilling under field conditions can be attributed, in part, to the greater fluidity of seedling mitochondrial membranes at low temperatures and concomitant conservation of respiratory energy through a lower rate of respiration. Assays of mitochondrial respiration and Arrhenius plots of mitochondrial respiration versus temperatures could be used to select cotton lines more tolerant to chilling temperatures.

Abstract not available

Thesis, (Ph. D.)--Oregon Graduate Institute of Science and Technology, 1998.

Thesis, (Ph. D.)--Oregon Graduate Institute, 1999.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.