ABSTRACT
The most of secreted proteins are exported by Sec translocase (secretion pathway). SecA ATPase is one of the most important subunit in the Sec translocase, which is preprotein translocase nanomotor that undergo membrane insertion and deinsertion to drive preprotein across the bacterial inner membrane, and SecA is indispensable to bacteria. It should be presumed that the compound which inhibits the activity of SecA ATPase probably can be used as the candidate of bactericide. A secA gene from Pseudomonas aerugi- nosa PAO1 was amplified and expressed in Escherichia coli BL21.19 (secA13). It has been shown that the wild-type SecA of Pseudomonas aeruginosa could fully complement the E. coli amber (secA13) mutant at the non-permissive temperature. So a cell level screening model targeting on SecA was established based on the above result. The inhibition of PaSecA ATPase activity was applied to validate the specificity of the cell-based method. Two positive samples based on both of cell and enzyme activities will be further studied.
ABSTRACT
This project is targeted on exploring some improving approaches to isolate and culture the microorganisms which are difficult to be isolated and cultured through the conventional ways. The results showed that betaine, sodium pyruvate, SOD and catalase are helpful for increasing the total number and variety of isolated strains. A kind of combined method was also used to isolate the micro-colony which can not be seen by naked eyes on the plates. Totally 52 Actinomycetes and 103 bacteria and 17 fungi were obtained from 4 soil samples using the above methods. 4. 325% microorganisms were obtained as positive strains to inhibit the growth of some kinds of test bacteria, which is higher than the percent using generally isolated ones. These microbial natural products may remain an important resource for the drug discovery.