The anti-tumor activities of a Cordyceps sinensis fungus extracts and the mechanism were studied in vitro. The cultivated mycelium were sequentially extracted by petroleum ether (PE) , ethyl acetate (EtOAc) , ethanol (EtOH ) and water. The results of MTT assay show that EtOAc extract inhibits significantly the proliferation of human premyelocytic leukemia cell HL-60 with an IC50≤25 μg/mL. The mechanism of EtOAc extract inhibiting the proliferation of HL-60 was studied by flow cytometer and Western blot. The results show that HL-60 cells are arrested at the G2/M phase after treatment with 25 μg/mL of EtOAc extract for 12-24 h, and the content of p34cdc2 decreases significantly.
Objective To investigate the synergistic effects of a biotic elicitor yeast extract and different abiotic elicitors (Ag+, Co2+ and alpha-amino isobutyric acid) on the production of tanshinones in Salvia miltiorrhiza hairy root. Method Different elicitors and their combinations were added to S. miltiorrhiza hairy root culture and the contents of three major tanshinones (crypotanshinone, tanshinone I and tanshinone II A) were analyzed by HPLC. Result The combinations of yeast extract with different abiotic elicitors had notable synergistic effects on the tanshinone I and tanshinone II A production but not on crypotanshinone. The combination of yeast extract and Ag+ (300 micromol x L(-1)) yielded the highest tanshinone I content, which was nearly 14-fold of the control, and the synergistic elicitation coefficient was 3.0. The combination of yeast extract and Co2+ (100 micromol L(-1)) led to the highest tanshinone IIA content, which was about 14.5-fold of the control, and the synergistic elicitation coefficient was 2.1. Only yeast extract combined with alpha-amino isobutyric acid (200 micromol x L(-1)) increased the crypotanshinone content more effectively than single elicitors. The highest crypotanshinone content was 1.28 mg x g(-1), about 30-fold of the control with a synergistic elicitation coefficient of 1.3. Conclusion The elicitation by the combination of a biotic elicitor and an abiotic elicitor can generate a synergistic effect, which is more effective than single elicitors to promote secondary metabolite production in plant tissue cultures.
Abstract The flow in a gas–liquid–solid circulating fluidized bed is self‐organised and manifests itself with clustering of particles and bubbles. The clustering behaviour in the fluidized bed at low solid holdups of resin particles was experimentally investigated with a high‐speed image measurement and treatment technique of complementary metal oxide semiconductor to enhance the fundamental understanding on such a flow. Several new physical quantities were suggested to characterise such ordered flow structures. The main findings are as follows. The clusters of solid particles largely exist as doublets and triplets, the mixed groups of particles and bubbles mostly exist as one bubble carrying two to four particles. Increasing superficial liquid velocity, particle diameter or density weakens the aggregation degrees of both particle and mixed clusters in the riser and downer, except that the increase of superficial liquid velocity enhances the mixed clustering behaviour in the riser. The climbing of the auxiliary liquid velocity or liquid phase viscosity intensifies the aggregation behaviour, except that the increase of liquid phase viscosity reduces the mixed clustering degree in the riser. The influences of superficial gas velocity and surface tension of liquid phase on the clustering behaviour seem to be a little complex and the trends are not simply increasing or decreasing. The life cycle of solid particle clusters in the GLS riser is not sensitive to the operation conditions, being around 0.07 s. The mixed clusters' life cycle is more sensitive to the conditions and physical properties of phases, changing from 0.02 to 0.07 s.
Candida tropicalis isolated from acclimated activated sludge was used in this study. Cell suspensions with 5 x 10(7) cells ml(-1) were irradiated by using a He-Ne laser. After mutagenesis, the irradiated cell suspension was diluted and plated on yeast extract-peptone-dextrose (YEPD) medium. Plates with approximately 20 individual colonies were selected, and all individual colonies were harvested for phenol biodegradation. The phenol biodegradation stabilities for 70 phenol biodegradation-positive mutants, mutant strains CTM 1 to 70, ranked according to their original phenol biodegradation potentials, were tested continuously during transfers. Finally, mutant strain CTM 2, which degraded 2,600 mg liter(-1) phenol within 70.5 h, was obtained on the basis of its capacity and hereditary stability for phenol biodegradation. The phenol hydroxylase gene sequences were cloned in wild and mutant strains. The results showed that four amino acids were mutated by irradiation with a laser. In order to compare the activity of phenol hydroxylase in wild and mutant strains, their genes were expressed in Escherichia coli BL21(DE3) and enzyme activities were spectrophotometrically determined. It was clear that the activity of phenol hydroxylase was promoted after irradiation with a He-Ne laser. In addition, the cell growth and intrinsic phenol biodegradation kinetics of mutant strain CTM 2 in batch cultures were also described by Haldane's kinetic equation with a wide range of initial phenol concentrations from 0 to 2,600 mg liter(-1). The specific growth and degradation rates further demonstrated that the CTM 2 mutant strain possessed a higher capacity to resist phenol toxicity than wild C. tropicalis did.
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