In Vitro Assay of Bacillus thuringiensis var. kurstaki otoxin Using a Plutella xylostella Cell Line
1993
Hochschulschrift
Zugriff:
81
Bacillus thuringiensis var. kurstaki HD-1 (Btk),when examined by scanning electron microscope (SEM), showed two observable forms of parasporal crystal; one is bipyramidal crystal, called P1 toxin, and the other cuboidal crystal, P2 toxin. The electrophoretic analysis of their crystal proteins found that the molecular weight of P1 is 135 KDa and t hat of P2 63 KDa. When activated with trypsin, P1 produced the toxic proteins with molecular weights of ca. 56-63 KDa. The lawn assay devised with cultured cells in agar plate and trypan blue layewed on the top surface,could rapidly detect the toxicity of the B. thuringiensis (Bt) toxic proteins. The concentration of a Plutella xylostella cell line (PX-1187) used in this assay had to be over 6x10 cell/dish ( 6 cm dia.) to produce the detectable reaction. On the other hand, when the cell concentration was lower than 2x10 cells/dish, no normal reaction was obtained. Using this lawn assay with the PX-1187 cell line, it was also found that the threshold dose of P1 against this line was 875 ng, while that of the activated P1 toxin was 245 ng, and P2 toxin 417 ng. Three different subclones of PX-1187, namely D、E、G, showed similiar degree of sensitivity to the Btkδ-endotoxin in comparison with their parental line. This assay system was not suitable for detecting the enhancing effect of some compounds, i.e., 0.125 % K CO, 0.5 % EDTA, 0.1 % ZnSO, 0.1 % CaCO, to Btk P1, when added to the assaying plates.
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In Vitro Assay of Bacillus thuringiensis var. kurstaki otoxin Using a Plutella xylostella Cell Line
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Autor/in / Beteiligte Person: | Lee, Chin-Sheng ; 李金生 |
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Veröffentlichung: | 1993 |
Medientyp: | Hochschulschrift |
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