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Sequential Immunosuppressive Activity of Bacterial Metabolites of an Entomopahogenic Bacterium, Xenorhabdus nematophila
- 언어ENG
- URLhttps://db.koreascholar.com/Article/Detail/288547
An entomopathogenic bacterium, Xenorhabdus nematophila, secretes at least eight bacterial metabolites, which have suppressive effects on insect immunity. This study quantified their sequential production during bacterial growth and analyzed their individual immunosuppressive activities against an insect host, Spodoptera exigua. X. nematophila exhibited a typical bacterial growth in both insect host and culture medium, in which eight metabolites were secreted in different time points. At early growth phase (6 to 12 h), Ac-FGV, Cis-cPY, PHPP and indole metabolites were detected in the culture broth. During early growth phase, PHPP was highly potent to inhibit phenoloxidase activity as well as nodule formation. At late growth phase (24 to 48 h), BZA, HPA, PY were detected at 10 – 140 ppm in the culture broth, their metabolites were highly potent to inhibit phospholipase A2 and to induce cytotoxicity to hemocytes. These results suggest that X. nematophila sequentially produces the immune suppressive metabolites, which cooperatively inhibit different steps of insect immune responses.
