| Summary: | 碩士 === 國立中興大學 === 生命科學系 === 94 === Bamboo, an important cash crop in Asia, is one of the fastest growing plants in this planet as a new shoot may grow rapidly over 3 feet per day. However, the mechanism of this burst of rapid growth is unclear. It was supposed that the rapid growth requires a huge amount of energy supplement. In order to understand how the energy metabolizes in young bamboo shoots, I intend to work on the isolated mitohcondria where the energy is mainly produced. Mitochondria isolated from young bamboo shoots of B. oldhamii and P. edulis were therefore compared. Firstly, using either succinate or NADH as substrate, the mitochondrial respiration rates of B. oldhamii were higher than those of P. edulis. B. oldhamii possessed about 2-fold complex I activity but similar external/internal NADH dehydrogenase activity as compared to P. edulis. Furthermore, the assembly of functional mitochondrial respiratory supercomplexes was studied using 1-D/2-D BN-PAGE, 1-D/2-D Tricine-SDS-PAGE, and in-gel activity staining with addition of digitonin. In both species, almost 87% of total complex I was assembled into supercomplexes. In B. oldhamii, about 40% of complex III was assembled into supercomplexes, but in P. edulis, about 50% was assembled into supercomplexes. Moreover, in assembling complex V, both species performed in a similar manner that 75% of complex V was assembled into supercomplexes. The amounts of the supercomplexes I+III2 and I+F1 in B. oldhamii were more than those in P. edulis. It may explain why the respiration rates using NADH as substrate in B. oldhamii were higher than those in P. edulis. In bamboo mitochondria, the novel supercomplexes I+III2+V2, I+III2+V, and I+F1 were be identified and never found in other species.
Identifying the mitochondrial SOD isoenzymes using 1-D CN-PAGE, 2-D native-PAGE, and in-gel activity staining, it was found that there were four Mn-SODs and three Cu/Zn-SODs in B. oldhamii whereas two Mn-SODs and three Cu/Zn-SODs in P. edulis. Two SOD protein spots excised from 2-D gels were further analyzed by MALDI-TOF MS.
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