TitleEnergy storage in Chlamydomonas reinhardtii measured with photoacoustic techniques
NameYan, Chengyi (author), Falkowski, Paul (chair), Schofield, Oscar (internal member), Gorbunov, Maxim (internal member), Rutgers University, Graduate School - New Brunswick,
DescriptionThe energy storage efficiencies of the reaction centers in the intact cells of Chlamydomonas reinhardtii wild type cell, PSI-less mutants and PSII-less mutants in microsecond time window were determined using pulsed, time-resolved photoacoustic techniques. The heat emission from the photochemical reaction can result in the positive thermal expansion photoacoustic signal, opposing the negative thylokoid volume contraction signal caused by electrostriction during the charge separation. In this present research, we observed that PSI differed strongly from PSII, both in thermal expansion and volume contraction. Similar to the bacterial reaction centre, PSI is marked with the large volume contraction but small thermal expansion, in contrast to the large thermal expansion but small volume contraction in PSII. For wild type, the volume contraction signal is dominant over the thermal expansion signal upon low pulse energy illumination at room temperature. In microsecond time scale, the energy storage efficiencies were estimated to be 36%, 80±5%, and 50±14% per trap in wild type, PSI and PSII, respectively. The different energy conversion efficiencies are probably attributed to the escape of the bound counterions from the particle surface in PSI and rapid electron transfer in PSII. In the present work, we conducted the photoacoustic experiments to study the energy storage in different photosystem with the intact cells of PSI-less and PSII-less mutants, instead of using either specific wavelength excitation light or PSII inhibitors (e. g. DCMU), which were commonly applied in the previous studies. We also proved photoacoustic techniques’ usefulness and convenience in the photosynthesis research, especially in electron transfer and some related thermodynamics studies.
NoteIncludes bibliographical references (p. 22-27)
Noteby Chengyi Yan
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work