Environ. Entomol. 22(2): 432-437 (1993) ABSTRACT Bacillus thuringiensis Berliner toxicity is a dose-dependent phenomenon, and the dose acquired by an individual is directly related to the quantity of treated food consumed. A bioassay was conducted using two Apium graveolens var. rapaceum (L.) cultivars to determine if the B. thuringiensis dose acquired by Spodoptera exigua (Hiibner) (Lepidopter...

A low frequency of chromosomal gene transfer from Bacillus thuringiensis to Bacillus cereus was detected by cell mating, with a tryptophan marker being the most frequently transferred gene among four that were tested. The process was resistant to DNase and was not mediated by cell filtrates. Among several B. thuringiensis subspecies tested, transfer was best with a derivative of B. thuringiensi...

An enzyme-linked immunosorbent assay was used to detect and quantitate the parasporal crystal toxins of Bacillus thuringiensis subspp. kurstaki and israelensis. The assay method described is extremely sensitive, accurate, and highly specific. With this technique, crystalline insecticidal proteins from several subspecies of B. thuringiensis were compared. The dipteran crystal toxin produced by B...

background: the incidence of mosquito-borne diseases and the resistance of mosquitoes to conventional pesticides have recently caused a panic to the authorities in the endemic countries. this study was conducted to identify native larvicidal biopesticides against culex pipiens for utilization in the battle against mosquito-borne diseases. methods: larvicidal activities of new indigenous bacillu...

Sixteen Escherichia coli clones were assayed against susceptible and Bacillus thuringiensis-resistant Culex quinquefasciatus larvae. The clones expressed different combinations of four genes from Bacillus thuringiensis ssp. israelensis; three genes encoded mosquitocidal toxins (Cry11Aa, Cry4Aa and Cyt1Aa) and the fourth encoded an accessory protein (P20). The cross-resistance spectra of the mos...

Little is known about genetic exchanges in natural populations of bacteria of the spore-forming Bacillus cereus group, because no population genetics studies have been performed with local sympatric populations. We isolated strains of Bacillus thuringiensis and B. cereus from small samples of soil collected at the same time from two separate geographical sites, one within the forest and the oth...

The insecticidal activity of the delta-endotoxins of 14 Bacillus thuringiensis strains belonging to 12 subspecies was determined against Pieris brassicae, Heliothis virescens, and Spodoptera littoralis. Larvae of P. brassicae were highly susceptible to purified crystals of strains of B. thuringiensis subsp. thuringiensis and B. thuringiensis subsp. morrisoni, whereas H. virescens responded best...