English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Most strains of the insecticidal bacteriumBacillus thuringiensis have a combination of different protoxins in their parasporal crystals. Some of the combinations clearly interact synergistically, like the toxins present inB. thuringiensis subsp.israelensis . In this paper we describe a novel joint activity of toxins from different strains ofB. thuringiensis . In vitro bioassays in which we used pure, trypsin-activated Cry1Ac1 proteins fromB. thuringiensis subsp.kurstaki , Cyt1A1 fromB. thuringiensis subsp.israelensis , andTrichoplusia ni BTI-Tn5B1-4 cells revealed contrasting susceptibility characteristics. The 50% lethal concentrations (LC50 s) were estimated to be 4,967 of Cry1Ac1 per ml of medium and 11.69 ng of Cyt1A1 per ml of medium. When mixtures of these toxins in different proportions were assayed, eight different LC50 s were obtained. All of these LC50 s were significantly higher than the expected LC50 s of the mixtures. In addition, a series of bioassays were performed with late first-instar larvae of the cabbage looper and pure Cry1Ac1 and Cyt1A1 crystals, as well as two different combinations of the two toxins. The estimated mean LC50 of Cry1Ac1 was 2.46 ng/cm2 of diet, while Cyt1A1 crystals exhibited no toxicity, even at very high concentrations. The estimated mean LC50 s of Cry1Ac1 crystals were 15.69 and 19.05 ng per cm2 of diet when these crystals were mixed with 100 and 1,000 ng of Cyt1A1 crystals per cm2 of diet, respectively. These results indicate that there is clear antagonism between the two toxins both in vitro and in vivo. Other joint-action analyses corroborated these results. Although this is the second report of antagonism betweenB. thuringiensis toxins, our evidence is the first evidence of antagonism between toxins from different subspecies ofB. thuringiensis (B. thuringiensis subsp.kurstaki andB. thuringiensis subsp.israelensis ) detected both in vivo and in vitro. Some possible explanations for this relationship are discussed.

Antagonism between Cry1Ac1 and Cyt1A1 Toxins of Bacillus thuringiensis