Purification and comparison of anti-feeding proteins between extracellular and intracellular protein of Xenorhabdus nematophila var. Pekingensis

摘要

Xenorhabdus nematophlia var. pekingensis CB6 strain is a symbiotic bacterium of Steinernema carpocaposae isolated from the soil of Beijing in China. This bacterium lives in the gut of the host nematodes. It is released from the gut of its host nematode to the insect hemocoel when the nematode penetrates into insect larvae. The bacteria multiply and secrete various kinds of metabolic substances, killing the insect and inhibiting the growth of other microorganisms. The CB6 strain showed high growth inhibition and high mortality with the larvae of Helicoverpa armigera, Plutella xylostella, Spodoptera exigua, et al. (Liu, et al. 2003Li et al. 2003). The bioactive substances were found in both extra-cellular and intracellular sections. Heat treatment orenzymatic degradation inactivated the bioactivity. This indicates that the active substances are proteins (Pan et al. 2004).