Methods for obtaining nucleotide sequences coding for polypeptides specifically active for larvae of S. littoralis

摘要

This invention provides a method for obtaining a nucleotide sequence that codes for the active part of a polypeptide specifically active for larvae of S. littoralis. The method comprises hybridizing at least one nucleotide probe to DNA from a strain of B. thuringiensis active against S. littoralis, wherein at least one nucleotide probe is derived from the 5′ part of a restriction fragment of a gene for δ endotoxin of B. thuringiensis strain aizawa 7-29, isolating the DNA from the strain of B. thuringiensis active against S. littoralis that hybridized to the probe, cloning the isolated DNA into a vector, and purifying the vector to thereby obtain the nucleotide sequence that codes for the active part of a polypeptide specifically active for larvae of S. littoralis, wherein the specifically active polypeptide has (1) a specificity index of less than 1.0 and (2) a higher specific toxic activity towards S. littoralis than the native crystal proteins of the strains aizawai 7-29 or berliner 1715.