›› 2005, Vol. 48 ›› Issue (3): 353-358.

• RESEARCH PAPERS • Previous Articles     Next Articles

Purification of insecticidal proteins from Xenorhabdus nematophila HB310 and detection of their insecticidal activity

WANG Qin-Ying1, NANGONG Zi-Yan1, LU Xiu-Jun1, LI Xiu-Hua2, LI Guo-Xun1, CUI Long1   

  1. College of Plant Protection, Agricultural University of Hebei
  • Online:2005-07-12 Published:2005-06-20

Abstract:

 The extracts of extracellular and intracellular insecticidal proteins from Xenorhabdus nematophila HB310 strain, an entomopathogenic bacterium symbiotically associated with entomopathogenic nematode Steinernema carpocapsae, appeared high toxic activity by oral or injectable infection against several species of insects. Two oral insecticidal proteins, toxinⅠand toxinⅡ, and another haemocoel insecticidal protein, toxin Ⅲ with injectable activity were purified from the intracellular protein extract by native-PAGE. The same three protein toxins also were obtained from the extracellular protein extract. There was only a single band for any of toxins above, but the results of SDS-PAGE showed four bands for toxinⅠ, three bands for toxinⅡ and one band for toxin Ⅲ, respectively. Bioassay results indicated that the oral insecticidal activity of toxinⅡ was higher than that of toxinⅠ to Helicoverpa armigera neonates. The injectable hemocoelic potency (LD50) of toxinⅢ was 0.18 μg/larva against Galleria mellonella fifth-instar larvae. The toxicity of toxinⅡ was stable under 50℃ in 10 min. The toxin Ⅲ was heat-stable to 70℃ in 10 min.

Key words: Xenorhabdus nematophila, protein toxins, purification, insecticidal activity