Cloning, expression, and characterization of prophenoloxidase from Antheraea pernyi.

Prophenoloxidase (PPO) is an essential enzyme in insect innate immunity because of its role in humoral defense. In this study, we have cloned a full-length cDNA of Antheraea pernyi prophenoloxidase (ApPPO) with an open-reading frame encoding 683 amino acids, and the deduced amino acid sequence of ApPPO exhibited a high similarity with those of lepidoptera. The expression of ApPPO was inducible so that the mRNA level was significantly upregulated in the microbial challenged tissues, including fat body, hemocytes, and midgut. To better investigate the enzymatic and immunological properties of ApPPO, recombinant ApPPO (rApPPO) was produced in Escherichia coli. Several functional verification experiments were performed after studying the enzymatic properties. It was found that rApPPO could be stimulated by the microbial challenged larvae hemolymph and then killed bacteria in the radial diffusion assay. Furthermore, rApPPO also induced the transcription of cecropins after injected into the larvae 24 h later.

Inhibition of matrine against gastric cancer cell line MNK45 growth and its anti-tumor mechanism.

Anti-tumor activity and mechanism of matrine is evaluated and investigated. MTT assay showed that the matrine was able to inhibit gastric cancer cell line MNK45 in a dose-dependent manner. The concentration required for 50% inhibition (IC50) was found to be 540 µg/ml. This anti-tumor function was achieved through modulation of the NF-κB, XIAP, CIAP, and p-ERK proteins expression in cell line MNK45. By western blot analysis, we found that expression of NF-κB, XIAP, CIAP, and p-ERK proteins in cell line MNK45 would vary with varying concentration of matrine. These protein interactions possibly play a pivotal role in the regulation of apoptosis, for which further detailed analyzes are need. These results overall indicate that matrine can be used as an effective anti-tumor agent in therapy of gastric cancer.