This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Walther, C J Articles by Nickerson, K W Search for Related Content PubMed PubMed Citation Articles by Walther, C J Articles by Nickerson, K W Agricola Articles by Walther, C J Articles by Nickerson, K W

 Previous Article  |  Next Article 

Appl Environ Microbiol. 1986 October; 52(4): 650-653

Analysis of mosquito larvicidal potential exhibited by vegetative cells of Bacillus thuringiensis subsp. israelensis.

ABSTRACT

Vegetative Bacillus thuringiensis subsp. israelensis cells (6 X 10(5)/ml) achieved 100% mortality of Aedes aegypti larvae within 24 h. This larvicidal potential was localized within the cells; the cell-free supernatants did not kill mosquito larvae. However, they did contain a heat-labile hemolysin which was immunologically distinct from the general cytolytic (hemolytic) factor released during solubilization of B. thuringiensis subsp. israelensis crystals. The larvicidal potential of the vegetative cells was not due to poly-beta-hydroxybutyrate. Instead, it correlated with the ability of vegetative cells to sporulate during the bioassays. No toxicity was observed when bioassays were conducted in the presence of chloramphenicol or streptomycin. It is unlikely that the vegetative cells sporulate in the alkaline (pH 9.5 to 10.5) larval guts after ingestion. B. thuringiensis subsp. israelensis is not an alkalophile; we have been unable to grow it in culture at pH values of greater than or equal to 9.5. Moreover, we have been unable to demonstrate formation of a protective capsule. However, bacteria may replicate in the gut fluids of dead or dying mosquito larvae because their alkaline gut pH values drop markedly after exposure to the B. thuringiensis subsp. israelensis crystal toxins.

This article has been cited by other articles:

• Kadavy, D. R., Plantz, B., Shaw, C. A., Myatt, J., Kokjohn, T. A., Nickerson, K. W. (1999). Microbiology of the Oil Fly, Helaeomyia petrolei. Appl. Environ. Microbiol. 65: 1477-1482 [Abstract] [Full Text]