3T3 Cells ; Animals ; Cell Membrane ; metabolism ; Mice ; Patch-Clamp Techniques ; Potassium Channels, Calcium-Activated ; radiation effects ; Radiation, Ionizing ; Wound Healing ; radiation effects

Objective　To study the effects of irradiation and W11-a12，a kind of repair-promoting drug，on anion-selective channel in membranes of mouse peritoneal macrophage. Methods　The activity of anion-selective channel was recorded from cell-attached patches with patch clamp techniques． Results　The effects of irradiation on anion-selective channel in membranes of peritoneal macrophage included：①decreasing the mean number of activated channels by the presence of zymosan; ②prolonging the mean time from stimulus to the opening of channels; ③depressing the opening of channels by decreasing open-state probability，shortening open-time and prolonging close-time． The effects of irradiation could partly be depressed by W11-a12. Conclusion　Irradiation will depress the anion-selective channel of peritoneal macrophage, which may be an important way to depress the function of macrophage．

Artemisinin,a new and a very potent antimalarial drug, is produced by the plant Artemisia annua L. with a very low yield ranging from 0.01% to 0.8% on a dry-weight basis. This makes artemisinin an expensive drug. Several studies reported chemical synthesis of the artemisinin, but none of them seems a viable economical alternative compared with the isolation of artemisinin from the plant. Hence, a higher artemisinin concentration in the plant is necessary for cheap antimalarial drug production. Many types of cyclic sesquiterpenes in Artemisia annua have been characterized to date, each derived from the common cyclic precursor FDP in a reaction catalyzed by a sesquiterpene synthase. Sesquiterpene synthases are widely regarded as the rate-determining regulatory enzymes in the pathways they participate, and a number of sesquiterpene synthases have been cloned from Artemisia annua up to now. This report is a brief review on the following sesquiterpene synthases: epi-cedrol synthase, amorpha-4,11-diene synthase, beta-caryophyllene synthase, (E)-beta-farnesene synthase, germacrene A synthase, as well as a new sesquiterpene synthase whose function remains largely unknown. The report is of help for a better understanding of metabolic engineering of Artemisia annua.
Alkyl and Aryl Transferases ; biosynthesis ; genetics ; Amino Acid Sequence ; Antimalarials ; Artemisia annua ; enzymology ; genetics ; Artemisinins ; metabolism ; Carbon-Carbon Lyases ; biosynthesis ; genetics ; Cloning, Molecular ; Escherichia coli ; genetics ; metabolism ; Molecular Sequence Data ; Recombinant Proteins ; biosynthesis ; genetics ; Sesquiterpenes ; isolation & purification