Aquatic effect duration study of Cry4 toxin with immunoassay and Aedes aegypti larval biotest

Ágnes Fejes, Eszter Takács, Gábor Fekete, Béla Darvas, Bruce S. Ferguson, Deepak Saxena, András Székács

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Bacillus thuringiensis subsp. israelensis (Bti) preparations are widely used for culicid larvae. There is no suitable commercially available analytical method for Cry4 toxin as active ingredient in Bti preparations. To overcome this limitation, an enzyme-linked immunosorbent assay (ELISA) was developed for quantitative determination of Cry4 toxin allowing a limit of detection (LOD) of ~2 ng ml-1 in water. Preconcentration of aqueous samples by lyophilisation resulted in low but reproducible recoveries (25.7±6.8%), and the practical LODs for Bti preparations VECTOBAC WDG granulate and VECTOBAC 12 AS suspension were found to be ~170 ng ml-1 and ~900 ng ml-1, respectively. ELISA determinations indicated a rapid decay in detectable concentrations of VECTOBAC WDG applied at 400 ng ml-1 concentration in surface water: detected concentrations decreased by 18% and 44% in 4 days in water collected from two locations, and dropped below LOD afterwards. Larval mortality of Aedes aegypti indicated a continuous decrease even thereafter. Thus, quantitative Cry4 toxin detection facilitates proper timing and frequency of treatments to achieve optimal efficacy.

Original languageEnglish
Pages (from-to)207-222
Number of pages16
JournalAquatic Insects
Volume34
Issue numberSUPPL. 1
DOIs
Publication statusPublished - Jun 1 2012

Keywords

  • Aedes aegypti
  • Bacillus thuringiensis subsp. israelensis
  • Cry4 toxin
  • ELISA
  • biotest
  • mosquito larva

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science
  • Insect Science

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