Efficient expression of mosquito-larvicidal proteins in a gram-negative bacterium capable of recolonization in the guts of Anopheles dirus larva

• Published in: Applied microbiology and biotechnology Vol. 51; no. 1; pp. 79 - 84
• Main Authors: Khampang, P, Chungjatupornchai, W, Luxananil, P, Panyim, S
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01.01.1999; Springer Nature B.V
• Subjects: Animals; Anopheles - microbiology; Anopheles dirus; Bacillus sphaericus; Bacillus thuringiensis - metabolism; Bacillus thuringiensis israelensis; Bacteria; Bacterial Proteins - biosynthesis; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Toxins; Biological and medical sciences; Biological control; biological control agents; Blotting, Western; Cloning, Molecular; Control; cryIVB gene; Culicidae; Electroporation; Endotoxins - biosynthesis; Enterobacter; Enterobacter - genetics; Enterobacter - growth & development; Enterobacter - metabolism; Enterobacter amnigenus; Freshwater; Fundamental and applied biological sciences. Psychology; Hemolysin Proteins; insect control; Intestines - microbiology; Larva - microbiology; Microbiology; mosquito larvicidal proteins; Mosquitoes; Pest Control, Biological; Phytopathology. Animal pests. Plant and forest protection; Plasmids - administration & dosage; Protozoa. Invertebrates; Recombinant Proteins - biosynthesis; Species Specificity; Recombinant microorganism; Toxicity; Insecta; Biological control; Floating line; Bacillaceae; Gene expression; Bacillus sphaericus; Culex quinquefasciatus; Toxin; Bacillales; Arthropoda; Culicidae; Bacteria; Isolation; Parasporal body; Invertebrata; Digestive tract; Diptera; Colonization; Enterobacteriaceae
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s002530051366

The gram-negative bacterium, An11/2 G1, isolated from the guts of Anopheles dirus mosquito larvae, was identified as Enterobacter amnigenus. The E. amnigenus was able to recolonize in the gut of An. dirus larva but not in those of Aedes aegypti and Culex quinquefasciatus larvae. It was able to float in water for a longer period than Bacillus thuringiensis subsp. israelensis and Bacillus sphaericus. These are desirable characteristics for a delivery vehicle of mosquito-larvicidal toxins for the control of mosquito larvae, and E. amnigenus was therefore used as a host to express the cryIVB gene of B. thuringiensis subsp. israelensis and the binary toxin genes of B. sphaericus. The recombinant E. amnigenus produced a high level of CryIVB protein, which was toxic to larvae of Ae. aegypti and An. dirus. Another E. amnigenus producing the 51-kDa protein of B. sphaericus was toxic to larvae of An. dirus and Cx. quinquefasciatus. The recombinant plasmids were stable in E. amnigenus without the presence of selective pressure for at least 23 generations. The recombinant E. amnigenus should represent a desirable biological agent for controlling mosquito larvae.