The glycoprotein toxin of Bacillus thuringiensis subsp. israelensis indicates a lectinlike receptor in the larval mosquito gut.
The mosquito-active protein crystals produced by Bacillus thuringiensis subsp. israelensis contain covalently attached aminosugars which are critical for their larvicidal activity. The 50% lethal concentrations toward Aedes aegypti larvae were increased up to 10-fold by mild periodate treatment, up to 40-fold by forming the protein crystals in the presence of tunicamycin, and up to 7-fold by the presence during the mosquito bioassays of N-acetylglucosamine or its trimer, triacetylchitotriose. Periodate-treated crystals and crystals formed in the presence of tunicamycin had greatly reduced binding capacities for wheat germ agglutinin, an N-acetylglucosamine-specific lectin. These results suggest that the B. thuringiensis subsp. israelensis glycoprotein toxin binds to a lectinlike receptor in the larval mosquito gut. Furthermore, the distinct lectin-binding patterns exhibited by diptera-active versus lepidoptera-active B. thuringiensis crystals suggest that host specificity for the microbial insecticides is determined, in part, by the carbohydrate portion of their glycoprotein crystals.
Muthukumar
G
G
School of Biological Sciences, University of Nebraska, Lincoln 68588-0118.
Nickerson
K W
KW
D000330:Aedes / Q000378:metabolism*; D000606:Amino Sugars / Q000378:metabolism; D000818:Animals; D001413:Bacillus thuringiensis; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000378:metabolism*; D001427:Bacterial Toxins / Q000378:metabolism*; D004731:Endotoxins; D006023:Glycoproteins / Q000378:metabolism; D006460:Hemolysin Proteins; D007814:Larva / Q000378:metabolism; D037102:Lectins / Q000378:metabolism; D010084:Oxidation-Reduction; D010504:Periodic Acid / Q000494:pharmacology; D010572:Pest Control, Biological; D011975:Receptors, Mitogen / Q000378:metabolism; D014415:Tunicamycin / Q000494:pharmacology
D000606:Amino Sugars; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006023:Glycoproteins; D006460:Hemolysin Proteins; D037102:Lectins; D011975:Receptors, Mitogen; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D010504:Periodic Acid; D014415:Tunicamycin