Bacillus subtilis as a host for mosquitocidal toxins production

Abstract

Aedes albopictus transmits several arboviral infections. In the absence of vaccines, control of mosquito populations is the only strategy to prevent vector-borne diseases. As part of the search for novel, biological and environmentally friendly strategies for vector control, the isolation of new bacterial species with mosquitocidal activity represents a promising approach. However, new bacterial isolates may be difficult to grow and genetically manipulate. To overcome these limits, here we set up a system allowing the expression of mosquitocidal bacterial toxins in the well-known genetic background of Bacillus subtilis. As a proof of this concept, the ability of B. subtilis to express individual or combinations of toxins of Bacillus thuringiensis israelensis (Bti) was studied. Different expression systems in which toxin gene expression was driven by IPTG-inducible, auto-inducible or toxin gene-specific promoters were developed. The larvicidal activity of the resulting B. subtilis strains against second-instar Ae. albopictus larvae allowed studying the activity of individual toxins or the synergistic interaction among Cry and Cyt toxins. The expression systems here presented lay the foundation for a better improved system to be used in the future to characterize the larvicidal activity of toxin genes from new environmental isolates.

Spore-Based Probiotic Bacillus subtilis: Current Applications in Humans and Future Perspectives

“…Through its close association with plants, and also by releasing a multitude of airborne spores, the species easily finds its way into the gastrointestinal (GI) tract of animals. It has been isolated from the GI contents and feces of multiple species of insects [4,5], fish [6], birds [7], and mammals [8][9][10] in their natural environments. The wide distribution of B. subtilis can be attributed to three major characteristics of the species.…”

Biosynthesis of silver nanoparticles mediated by entomopathogenic bacteria: Bacillus cereus VCRC 641 against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus

“…Proteinaceous toxins produced by certain bacteria such as Bacillus thuringiensis are used to kill mosquito larvae [6]. The other mosquitocidal bacteria include Bacillus amyloliquefaciens [7], Bacillus subtilis [8], Bacillus sphaericus [9], Lysinibacillus sphaericus [10] and Bacillus cereus [11]. Multiple crystal (Cry) proteins and cytolytic (Cyt) toxins in this Bacillus induce critical toxicity in mosquito larvae.…”

“…Cry proteins primarily target the outer membrane of gut cells, causing cell membrane leakage, gut function disruption, and larval mortality. Cyt toxins cause larval mortality through cytolytic action at the cell membrane [8,9,11,12]. BinA and BinB proteins are the main toxins of L. B. sphaericus, which have cytopathological effects on the midgut and cause larval mortality [13].…”

Identification of a Novel Brevibacillus laterosporus Strain With Insecticidal Activity Against Aedes albopictus Larvae

“…The major pitfalls of B. thuringiensis var. israelensis is its sensitivity to UV-damage ( Myasnik et al, 2001 ), which required the development of stabilizing formulations ( Lacey, 2007 ) and biotechnological approaches, including transgenic crops or recombinant bacteria expressing B. thuringiensis toxins ( Federici et al, 2003 ; Sanahuja et al, 2011 ; Ursino et al, 2020 ).…”