Production of 5-aminolevulinic acid from glutamate by overexpressing HemA1 and pgr7 from Arabidopsis thaliana in Escherichia coli.

The important metabolic intermediate 5-aminolevulinic acid (ALA) is useful for cancer treatment or plant growth regulation and has consequently received much attention. In this study, we introduced the HemA1 and pgr7 genes from the higher plant Arabidopsis thaliana into recombinant Escherichia coli to overproduce extracellular 5-aminolevulinic acid via the C5 pathway. In the E. coli BL21 (DE3) strain background, the ALA concentration of the strain expressing both HemA1 and pgr7 was the highest and reached 3080.62 mg/L. Among the 7 tested hosts, ALA production was the highest in E. coli Transetta (DE3). In E. coli Transetta GTR/GBP, the expression levels of zwf, gnd, pgl and RhtA were upregulated. Glutamate induced the expression of the GltJ, GltK, GltL and GltS genes that are in involved in glutamate uptake. The recombinant E. coli Transetta GTR/GBP was able to produce 7642 mg/L ALA in modified minimal medium supplemented with 10 g/L glutamate and 15 g/L glucose after 48 h of fermentation at 22 °C. The results provide persuading evidence for the efficient production of ALA from glucose and glutamate in E. coli expressing A. thaliana HemA1 and pgr7. Further optimization of the fermentation process should be done to improve the ALA production to an industrially relevant level.

Microscopic Identification of Medicinal Material of Herba Rabdosiae Serrae / 广州中医药大学学报

[Objective] To make a microscopic identification of medicinal material of Herba Rabdosiae Serrae (HRS) from different plant resources. [Methods] The dry leaves of the whole, the middle part and the upper-middle part from the plants of Isodon serra (Maxim.) Kudo, Isodon striatus (Benth.) Kudo, Isodon lophanthoides var. geradianus (Benth.) Hara, and Isodon lophanthoides Hara var. graciliflorus (Benth.) Hara were sliced by different methods. Structure of leaf epidermis, the transverse section of leaf and structure of leaf powder were observed under light microscope. [Results] There existed differences in epidermal cells, stomata distribution, nonglandular hair, glandular hair, small glandular hair and glandular scale of leaf epidermis from four kinds of medicinal plants of Herba Rabdosiae Serrae . And there also existed differences in epidermal cells, anticlinal wall and external-section wall of epidermal cells, nonglandular hair, glandular hair, glandular scale, stomata distribution, mesophyll, main vessels, and vascular bundle of leaf transverse section, as well as in epidermal cells, stomata distribution, glandular scale, nonglandular hair, glandular hair and ducts of leaf powder from four kinds of medicinal plants of Herba Rabdosiae Serrae. [Conclusion] Medicinal plants of different kinds of Herba Rabdosiae Serrae have different microscopic identification structure in leaf epidermis, leaf transverse section and leaf powder.

Strategy for Screening Leading Compounds From Botanicals / 中国药房

OBJECTIVE:To discuss the strategy for screening new leading compounds and discover the novel drug candidates,which have the independent intelligent property right,from botanicals METHODS:Screening the new leading componds from the single plant which plays the main therapeutic role in classical prescriptions or proved recipes were reviewed RESULTS:The results showed that the frequency of use of certain kinds of plant was higher than that of the others in treatment of certain disease,it is hypothesized that the plant may contain the active ingredient for the therapy of certain kinds of disease CONCLUSION:Screening new leading compound from Chinese materia medica is a shortcut with less risk,which may promote the development of new drugs in China