Study of ganoderic acid and volatiles biosynthesis during heat stress-induced apoptosis

• Main Authors: Wei-Zhi Hsu, 許維喆
• Other Authors: Jun-Yi Yang
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/dyyc9y

碩士 === 國立中興大學 === 生物化學研究所 === 106 === Ganoderma lucidum (G. lucidum ) is a traditional Chinese medicine that has been used in Asia for a long time. Its major pharmaceutical ingredient, ganoderic acids (GA), belongs to triterpenoid and it’s pharmalogical activities such as anti-cancer, anti-inflammation and liver protection has been proved. In plants, several studies indicated that fungal cell walls induced apoptosis and secondary metabolite production. However, it remains unknown for regulation of apoptosis and the secondary metabolites biosynthesis. This study investigates the regulation of heat-induced apoptosis and GAs biosynthesis by cell membrane fluidity and calcium signaling. Our results showed that intracellular calcium was increased after heat stress by using calcium fluorescent dye (Fluo-3AM). 50 mM EGTA pretreatment reduce intracellular calcium concentration caused by heat treatment. By HPLC analysis, our results showed that 50 mM EGTA reduced heat-sress induced GAs production. These results indicated that extracellular calcium ions is involved in the regulation of GAs biosynthesis under heat stress. Our data also showed that calcium signaling proteins, calmoduiln and calcinurein, were not involved in heat-stress induced GAs biosynthesis by using inhibitor of calmoduiln and calcinurein, cyclosporine A and chloropomazine, respectively. In addition, we proved that calcium released from organelles was not involved in heat-stress induced GAs biosynthesis. Another part of this thesis investigate the volatile compounds in G. lucidum. Whether apoptosis regulates volatile compounds biosynthesis is unknown. Previous study indicated that aspirin induced apoptosis and volatiles production in G. lucidum. Our results showed that heat stress induced different profile of volatiles production as compared with aspirin treatment. These results indicate apoptosis regulates volatile biosynthesis in fungi.