Regulation Of Superoxide Dismutase Induction In Garlic Cells & Expression Of Recombinant Trypsin Inhibitor Gene From Wild Rice

For developing national pharmaceutical biotechnology of anti-ageing and anti-AIDS disease, induced overproduction and cooperative regulation of garlic SOD as well as in vitro recombination and heterologous expression of wild rice TI gene were investigated. Results have shown that both physical and chemical stress were capable of effectively increasing their SOD activity in cultured cells, in which, the cellular SOD activity induced by chilling and heat shock were raised for 67% and 30%, respectively, and the SOD activity in cells induced by the disturbed chilling and interrupted heat shock were as 1.72 and 1.71 folds as the control. In cells induced by salicylic acid, the SOD activity was increased by 84%, and by the interaction of salicylic acid with chilling or with heat shock, elevated by 2.08 or 3.65 times, when compared with the control. These results would provide a basis for the large-scaled fermentative production of SOD, and might be a prerequisite for the further optimization of cell culture and induction. It was also found that physical or chemical stress initially invoked a transient release of H2O2 into the medium, and then stimulated a continuous elevation of extracellular POD activity. During the striking early phase of oxidative stress, both activities of extra- and intracellular POD were dynamically changed as a mode of "outside-elevation and inside-decline". The free radical generators, in a positive pattern, and free radical scavengers, in a negative pattern, functioned as antagonists, and thereby affected and regulated levels of H2O2. The induced extracellular POD activity by methyl viologen was higher, but by thiourea was lower, than the control.. While salicylic acid raised the level of H₂O₂ by inhibition of CAT activity, cysteine declined it by the induction of this enzyme. GSSG and NADP might act as positive effectors for controlling the H2O2 level, and GSH and NADPH, however, the negative effectors. The extra- and intracellular levels of H₂O₂ might be individually controlled by POD and CAT. As a conclution, H₂O₂ an oxidative stress signal transduction molecule in plant cells might be convinced.The sequence analysis of the wild rice TI gene have indicated that not only a extensive homology to cultivated rice was found (the homology was 74% at the amino acid level), but partially homologies to other compared plant TI and some other seed storage proteins (especially certain physically impotant plant proteins) were disclosed. The similarity of wild rice TI with animal and human TI in the kind of amino acid residues flunked the active site of TI was discovered. A standard classification system of seed storage proteins was also suggested according to the...