104 research outputs found
Mortality of Oryzophagus oryzae (Costa Lima, 1936) (Coleoptera: Curculionidae) and Spodoptera frugiperda (J E Smith, 1797) (Lepidoptera: Noctuidae) Larvae Exposed to Bacillus thuringiensis and Extracts of Melia azedarach
The use of bacterial larvicides in mosquito and black fly control programmes in Brazil
Necrotrophism Is a Quorum-Sensing-Regulated Lifestyle in Bacillus thuringiensis
How pathogenic bacteria infect and kill their host is currently widely investigated. In comparison, the fate of pathogens after the death of their host receives less attention. We studied Bacillus thuringiensis (Bt) infection of an insect host, and show that NprR, a quorum sensor, is active after death of the insect and allows Bt to survive in the cadavers as vegetative cells. Transcriptomic analysis revealed that NprR regulates at least 41 genes, including many encoding degradative enzymes or proteins involved in the synthesis of a nonribosomal peptide named kurstakin. These degradative enzymes are essential in vitro to degrade several substrates and are specifically expressed after host death suggesting that Bt has an active necrotrophic lifestyle in the cadaver. We show that kurstakin is essential for Bt survival during necrotrophic development. It is required for swarming mobility and biofilm formation, presumably through a pore forming activity. A nprR deficient mutant does not develop necrotrophically and does not sporulate efficiently in the cadaver. We report that necrotrophism is a highly regulated mechanism essential for the Bt infectious cycle, contributing to spore spreading
Histopathological and ultrastructural effects of delta-endotoxins of Bacillus thuringiensis serovar israelensis in the midgut of Simulium pertinax larvae (Diptera, Simuliidae)
Two new Brazilian isolates of Bacillus thuringiensis toxic to Anticarsia gemmatalis (Lepidoptera: Noctuidae)
Medium for the production of primary powder of Bacillus thuringiensis subsp. israelensis
Screening of the insecticidal activity ofBacillus thuringiensis strains against the egyptian cotton leaf wormSpodoptera littoralis
Histopathologie de l'action de la δ-endotoxine deBacillus thuringiensis var.Israelensis sur les larves d'Aedes aegypti (Dip.:Culicidae)
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