The Resistance Of Par Amecium Sp. To Algae Endophytic Fungi Secondary Metabolites

Paramecium sp. is a kind of extremely protozoa in cilia. The researchers often like to use it as a biological indicator for some characteristics of them. First, Paramecium sp.exist anywhere of the world, and we can get it easily and conveniently. Second, Paramecium sp. has more strong vitality than other single-celled animals, it is easier to cultivate. Third, the individual is bigger than other single-celled animals, it is easier to be observed. Fourth, paramecium sp. is more sensitive to toxicant. Fifth, compared to the general chemical methods, paramecium sp. can be more lively. Marine microorganisms live in a very different environment from the land, low temperature, high pressure, lack of oxygen, high temperature, and that lead marine microorganisms to a completely different and unique and also very complex metabolic pathways, adapt and survive ways. So they can produce many rare chemical that has special structure and varieties of biological activity.In this dissertation,two marine algicolous fungal strain including Trichoderma Longibrarachiatum and Aspergillus nomius were studied for further investgation of chemical constituents. Most of the isolated compounds were preliminary screened on their bioactivities. As a result, ten known compounds were isolated from the cultures by silica gel column chromatography,Sephadex LH-20column chromatography, preparative thin-layer chromatography, and high performance liquid chromatography. The structures of these compounds were mainly identified by1H,13C, and DEPT NMR techniques. The paramecium sp. resistance experiment showed that the IC50of ergosterol peroxide, cerevisterol, P-sitosterol,2-anhydromevalonic acid, and harziane are1.958μg/mL,2.108μg/mL,1.907μg/mL,5.613μg/mL,1.153μg/mL. The IC50of ergosterol peroxide,(24R)-24-Methyl cholesta-4,22-dien-3-one, stigmasta-4,22-dien-3-one, stigmast-4-en-3-one were2.827μg/mL,2.376μg/mL,2.245μg/mL. From the results we can see that the secondary metabolites of endophytic fungi of algae can kill paramoecium sp., and in a certain range, the fatality rate and concentration of compounds appear to linear relation. Terpenoids showed the strongest poison effect on paramecium sp.. The effect of nonsteroidal compounds were stronger than ketone compounds, and paramecium sp. showed a most strongest resistance to2-anhydromevalonic acid.