Some strains of the Gram-positive spore-forming bacterium Bacillus thuringiensis are very toxic to various insect larvae. The insecticidal activity is determined by different cytoplasmic insoluble proteins produced during sporulation which aggregate to form parasporal crystals (E Schnepf et al. 1998 Microbiol Mol Biol Rev 62: 775-806). A few strains of B. thuringiensis are used as bioinsecticides to control pests and vector insects in the orders Diptera, Lepidoptera and Coleoptera (PAW Martin & RS Travers 1989 Appl Environ Microbiol 55: 2437-2442) and more recently new isolates of B. thuringiensis have been shown to be active against Hymenoptera, Homoptera, Orthoptera and Mallophaga, as well as nematodes, mites and pro-Partially supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico.
IntroductionLysinibacillus sphaericus is a highly effective and specific bioinsecticide used for the control of Culicidae larvae.ObjectiveThis study aimed to identify and characterize L. sphaericus strains isolated from Culex quinquefasciatus larvae in Brazil.MethodsC. quinquefasciatus larvae were collected from streams in the urban area of São Paulo state. L. sphaericus strains were identified through cytomorphology, biochemical, and physiological analyses. Qualitative bioassays were performed to evaluate the toxicity of the strains against C. quinquefasciatus. The crystal compound protein pattern of L. sphaericus strains was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Five reference strains were used as standards in all tests performed. Repetitive extragenic palindromic elements-polymerase chain reaction (REP-PCR) was utilized in an attempt to differentiate pathogenic and nonpathogenic isolates.ResultsTwenty-one strains were isolated. Only one presented toxic activity against C. quinquefasciatus. REP-PCR results identified 23 patterns among the 26 strains used in the study, and the fragment analysis showed low similarity (16%) between L. sphaericus isolates and the five reference strains.ConclusionComparison of strains isolated in this study using REP-PCR showed a low similarity to other strains, demonstrating the high intraspecific variability for L. sphaericus.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.