An investigation of defense proteins from mushrooms

Mushrooms produce a variety of proteins with interesting biological activities. They include lectins, antifungal proteins, ribonucleases, ubiquitin-like proteins, hemolysins and other peptides.; An 18-kDa lectin, with an N-terminal sequence similar to some lectins and fungal immunomodulatory proteins, was isolated from Ganoderma capense. It exhibited potent mitogenic activity toward mouse splenocytes, and antiproliferative activity toward leukemia and hepatoma cells.; A 13-kDa lectin was isolated from Collybia veultipes. Its N-terminal sequence shows some similarity to other fungal immunomodulatory proteins. It stimulated [3H-methyl] thymidine uptake by mouse splenocytes and inhibited proliferation of leukemia cells.; A 27.5-kDa antifungal protein, with an N-terminal sequence similar to heat shock protein and endoglucanase, was purified from Lentinula edodes. It inhibited fungal growth and exerted an inhibitory activity on HIV-1 reverse transcriptase and proliferation of leukemia cells.; A 14.4-kDa antifungal protein was purified from Agrocybe cylindracea . It exerted antifungal activity but lacked inhibitory activity against bacteria when tested up to 300 muM. It attenuated the activity of HIV-1 reverse transcriptase.; A 12-kDa ribonuclease was purified from Pleurotus sajor-caju . The ribonuclease inhibited fungi growth and two species of bacteria, Pseudomonas aeruginosa and Staphylococcus aureus. It reduced the viability of hepatoma and leukemia cells and inhibited translation in a cell-free rabbit reticulocyte lysate system.; A 7-kDa ubiquitin-like protein was purified from Agrocybe cylindracea . It showed antiproliferative activity on leukemia and hepatoma cell lines, and enhanced nitric oxide production in murine peritoneal macrophages.; A 17-kDa hemolysin was purified from Pleurotus eryngii. It exhibited cytotoxicity toward leukemia cells but not toward fungi. It exhibited antibacterial activity against Bacillus species.; This study demonstrates that different types of defense proteins with diverse biological activities are produced by mushrooms. Some overlap is observed in the spectra of biological activities of the same type of defense proteins. The results of protein characterization provide crucial information for future genetic manipulation in agricultural and food industries. Studies of the in vitro action of the abovementioned defense proteins on fungi, bacteria, viral enzyme, immune cells and cancer cells indicate that the proteins are potentially exploitable drug agents.