ABSTRACT
AIMS: The aim of this work was to investigate the effect of cry3A promoter on the expression of cry1Ac in Bacillus thuringiensis chromosome and stably enhance the production of different cry genes under the control of cry3A promoter. METHODS AND RESULTS: The cry1Ac gene, which is specific to Lepidopteran larvae, was integrated into the chromosome of a B. thuringiensis plasmid-free and acrystalliferous strain BMB171, under the control of cry3A promoter and cry1Ac promoter, respectively. The expression of cry1Ac genes in the chromosome of host strain was investigated. The results from sodium dodecyl sulfate-polyacrymide gel electrophoresis, crystal observation and bioassay showed that either integrated with cry3A promoter (cry3Apro-cry1Ac) or with its native promoter (cry1Acpro-cry1Ac), cry1Ac gene could efficiently and stably express in the chromosome. The production of cry3Apro-cry1Ac gene was higher than that of cry1Acpro-cry1Ac gene. CONCLUSIONS: The cry3A promoter enhanced the expression of cry1Ac gene efficiently either on the chromosome or on the plasmid in B. thuringiensis strain. SIGNIFICANCE AND IMPACT OF THE STUDY: So far, the comparative studies on cry3A promoter and other cry promoters were carried on B. thuringiensis plasmids. This system offers an additional method for potentially improving the efficacy of B. thuringiensis insecticidal proteins efficiently, stably and safely.
Subject(s)
Bacillus thuringiensis/genetics , Bacterial Proteins/genetics , Bacterial Toxins/genetics , Chromosomes, Bacterial/genetics , Endotoxins/genetics , Hemolysin Proteins/genetics , Promoter Regions, Genetic/genetics , Animals , Bacillus thuringiensis/ultrastructure , Bacillus thuringiensis Toxins , Bacterial Proteins/pharmacology , Bacterial Toxins/pharmacology , Culture Media , DNA, Bacterial/genetics , Electrophoresis, Polyacrylamide Gel/methods , Endotoxins/pharmacology , Gene Expression Regulation, Bacterial/genetics , Genetic Vectors/genetics , Genomic Instability/genetics , Hemolysin Proteins/pharmacology , Insecticides/pharmacology , Lepidoptera/drug effects , Microscopy, Electron/methods , Plasmids/genetics , Recombination, Genetic/geneticsABSTRACT
A simple method of measuring the phase-modulation properties of liquid-crystal televisions (LCTV's) that vary with the driving gray-scale level is presented. The theoretical derivation of the method is described. Compared with previous methods of measuring the phase shifts of LCTV's, this technique is noninterferometric and very simple. The experimental results of a LCTV are shown.
