The xylanase gene of Bacillus subtilis B10 which had an excellent capacity for degumming ramie fibres was cloned by PCR amplification. The xylanase gene was cloned into vector pBluescript II KS+ and the CaMV 35S promoter was inserted in front of the gene, and the expression vector pKS-35SXYHyg was constructed successfully after the Hyg~(r) gene was inserted into the multi-cloning sites of pBluescript II KS+. The expression vector was linearized and transformed protoplasts of Aspergillus niger strain An1. Hygromycin-resistant transformants were generated and the integration of xylanase gene was confirmed by genomic Southern blotting analysis. Compared with An1, the xylanase activity of the transformant AT1 was increased more than trebled, and the residual gum content was decreased by 55.18% after the ramie was treated by culture supernatants from AT1.

In our program to search for new AMP-activated protein kinase (AMPK) activators from plants that exert potential anticancer property, we found that an EtOAc extract of Myristica fragrans (nutmeg) activated AMPK enzyme in human breast cancer MCF-7 cells. Two major diarylbutane-type lignans, macelignan and meso-dihydroguaiaretic acid (MDGA), were isolated as active principles from this extract. Treatment of breast cancer cells with two compounds induced cellular apoptosis, evidenced by cleavage of poly-(ADP-ribose) polymerase (PARP) and Ser 15 phosphorylation of p53. Moreover, macelignan and MDGA significantly inhibited the colony formation of MCF-7 breast cancer cells on soft agar. Intraperitoneal injection of macelignan and MDGA (20 mg/kg) suppressed the tumor growth of 4T1 mammary cancer cells. These results indicate that the chemopreventive effects of two major diarylbutane-type lignans from Myristica fragrans (nutmeg) may be associated with induction of apoptosis presumably through AMPK activation.
Agar ; AMP-Activated Protein Kinases* ; Apoptosis ; Breast Neoplasms* ; Breast* ; Humans ; Injections, Intraperitoneal ; Lignans* ; MCF-7 Cells ; Myristica fragrans* ; Phosphorylation