Effect of Bacillus thuringiensis toxins on the membrane potential of lepidopteran insect midgut cells

• DOI: 10.1128/aem.63.5.1679-1684.1997
• Publication Date: 2020-01-06T18:27:58Z
• Authors: O Peyronnet; V Vachon; R Brousseau; D Baines; J L Schwartz; R Laprade
• Keywords: Bacillus thuringiensis; Lymantria dispar

To test whether the ability of Bacillus thuringiensis toxins to form pores in midgut epithelial cell membrane susceptible insects correlates with their vivo toxicity, we measured effects different on electrical potential apical freshly isolated midguts from gypsy moth (Lymantria dispar) and silkworm (Bombyx mori) larvae. In absence toxin, potential, a conventional glass microelectrode, was stable for up 30 min. It sensitive K+ concentration oxygenation external medium. Addition which L. dispar is highly [CryIA(a) CryIA(b)] or only slightly [CryIA(c) CryIC] caused rapid, irreversible, dose-dependent depolarization membrane. CryIF, whose toxicity towards unknown, CryIE, at best poorly active vivo, were also vitro. contrast, CryIB CryIIIA, coleopteran-specific had no significant effect. The basolateral-membrane unaffected by CryIA(a) CryIC when toxin applied basal side epithelium. B. mori midguts, apical-membrane abolished CryIA(a), larvae are susceptible, but CryIA(b) CryIA(c); they resistant, detectable Although technique discriminated between inactive toxins, required produce given effect varied much less extensively than sensitivity larvae, suggesting that additional factors influence toxins' level vivo.