Preparation of catalitaxol-deficient defective strains by using ultraviolet mutagenesis / 生物工程学报

Secondary metabolites of endophytic fungi FSN002 from Juglans mandshurica Maxim have excellent liver cancer resistance. Preparation of mutant strains is an important means to study the biosynthesis mechanism of catalitaxol. Fungal spores germinating young hyphae with 4 to 6 cells after culturing for 13 hours were used as starting materials of ultraviolet (UV) mutagenesis. UV light intensity and irradiation time have a linear relationship with fungal mortality. The two factors had no obvious interactions. When UV light was 90 000 μJ/cm2 and irradiation time for 6 s, the mortality of fungi was around 95%. Under the optimization mutation condition, two mutant strains were obtained, of which one lost the synthesis ability of catalitaxol completely, and the another synthetized only 16% catalitaxol of the wild strain. Our findings may serve basis for further study on the biosynthesis mechanism and efficient production of catalitaxol.

Isolation, identification and anticancer activity of an endophytic fungi from Juglans mandshurica / 中国中药杂志

The endophytic fungus named FSN006 was isolated from the inner bark of Juglans mandshurica. It grew quickly and formed circular colony on PDA plate. The upper side of the colony was white, while the lower side of the colony and the conditioned medium were light yellow as a result of significant yellow pigment substances were produced and secreted by the fungi. Green elliptic conidia appeared when cultured on CMX plate. Based on the morphology identification and ITS sequence, it was clear that this fungus belonged to the Deuteromycotina, HyPhomycetes, Moniliales, Trichoderma longibrachiatum. The conditioned medium of FSN006 showed a high anti-tumor ability against liver cancer cell-HepG2, and reached its IC50 concentration after being diluted 20 times, while the IC50 concentration of curcumine was(11.49 +/- 0.12) mg x L(-1). In addition, there was preeminent selective inhibiting effect against the normal liver cell strain HL-7702 and its caner counter strain HepG2. The inhibiting effect against strain HL-7702 was only one quarter of that against HepG2 at the concentration of IC50. Therefore, the fermentation of FSN006 may provide a possible way to produce anticancer drug with higher efficiency and lower toxicity.

Effects of fed-batch carbohydrate, nitrogen, phosphorus on growth of Taxus chinensis var. mairei cell during suspension culture / 中草药

Object To solve the problem that Taxus chinensis var. mairei (Lemee et L?vl.) Cheng et L. K.Fu grows slowly. Methods The consumption of phosphorus during the cell suspension culture and the effect of fed-batch carbohydrate, nitrogen and phosphorus on cell growth and living-cell activity were assayed. Results The carbohydrate was exhausted in the middle phase of suspension culture, dificiency of carbohydrate led to inhibition of cell growth in the late culture. Conclusion Compared with the control group, the cell growth rate and the cell density in the fed-batch carbohydrate group were increased significantly, and the cell growth rate was up to 83%.