Cloning and sequence analysis of the cyclomaltodextrinase gene from Bacillus sphaericus and expression in Escherichia coli cells

1993 ◽  
Vol 39 (2) ◽  
Author(s):  
Tetsuya Oguma ◽  
Asahi Matsuyama ◽  
Mamoru Kikuchi ◽  
Eiichi Nakano
Keyword(s):  
Escherichia Coli ◽  
Sequence Analysis ◽  
Bacillus Sphaericus ◽  
Expression In Escherichia Coli ◽  
Escherichia Coli Cells

Interaction of the Bacillus sphaericus mosquito larvicidal proteins

1990 ◽  
Vol 36 (12) ◽  
pp. 870-878 ◽  
Author(s):  
Elizabeth W. Davidson ◽  
Coreen Oei ◽  
Marian Meyer ◽  
Allan L. Bieber ◽  
John Hindley ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Sequence Analysis ◽  
Key Words ◽  
Culex Quinquefasciatus ◽  
Bacillus Sphaericus ◽  
Insecticidal Proteins ◽  
Posterior Midgut ◽  
Sds Page ◽  
Reduced Activity

Genes for 51.4- and 41.9-kDa insecticidal proteins of Bacillus sphaericus were separately cloned and expressed in Escherichia coli. Both proteins were required for toxicity. Approximately equal numbers of cells containing the 51.4- and 41.9-kDa proteins produced the greatest toxicity; excess 41.9-kDa protein did not affect toxicity, whereas excess 51.4-kDa protein reduced activity. Larvae were killed when 41.9-kDa protein was fed up to 24 h after the 51.4-kDa protein, but not when the order of feeding was reversed. Radiolabelled toxins bound in approximately equal amounts to the gastric caecum and posterior midgut of Culex quinquefasciatus larvae. Radiolabelled 51.4-kDa protein was rapidly degraded by ca. 12–13 kDa in the larval gut, while 41.9-kDa protein was degraded by 1–2 kDa. Nonreduced toxin extracted from B. sphaericus produced a band on SDS–PAGE of ca. 68–74 kDa that contained both 51.4- and 41.9-kDa proteins based on sequence analysis, and a band of ca. 51 kDa that contained primarily 41.9-kDa protein. Escherichia coli containing 51.4-kDa protein enhanced toxicity of the latter eluted SDS-PAGE band. These proteins may associate very strongly, and trace amounts of 51.4-kDa protein in preparations of 41.9-kDa protein from B. sphaericus may be responsible for the previously reported toxicity of the latter. Key words: Bacillus sphaericus, toxin, mosquito, cloning.

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