Seleção de espécies bacterianas cultiváveis, simbiontes de Anopheles darlingi (Root, 1926), para o controle da malária por paratransgênese

Abstract

Despite positive advances in the fight against malaria each year, this disease is still one of the most lethal among vector-borne parasitic diseases worldwide, with the highest death records in Africa, caused mainly by Plasmodium spp. and transmitted by Anopheles spp. Among the ways of controlling this disease, paratransgenesis stands out as a new and promising alternative that aims to inhibit the development of parasites within the vector through the action of genetically modified bacteria. This new approach is being successfully conducted against Plasmodium spp. in laboratory on the African continent. Due to the constant records of malaria cases in the Brazilian Amazon, this region it could be also the target of paratransgenic approaches, with the objective of blocking the development of Plasmodium vivax within the body of Anopheles darlingi, the main responsibles for this disease in this region. In this sense, the first step should be directed towards obtaining of symbionts bacteria of A. darlingi, which can be transmitted horizontally and vertically in mosquitoes and not being pathogenic to humans. Such characteristics are essential in paratransgenesis. In this sense, this work aimed to select cultivable bacterial species, symbionts of A. darlingi to control malaria by paratransgenesis. Bacterial isolations were performed on samples associated with the larval development environment, as well as on the body of A. darlingi, in order to identify recurrent species in the different samples. After sequencing the 16S rRNA gene of the isolated colonies, 179 species were identified in the samples from Coari and Manaus, which constitute 83 different species, 12 from Coari and 71 from Manaus. The predominant species in all samples, from Coari and Manaus, were: Acinetobacter nosocomialis; Enterobacter asburiae; Klebsiella pneumoniae; Serratia marcescens; Bacillus cereus; Pantoea dispersa; Elizabethkingia miricola; Klebsiella variicola; Stenotrophomonas pavanii and Pantoea agglomerans. After analyzing some criteria, fundamental for use in paratransgenesis, such as non-pathogenicity to humans, the bacterial strains S. marcescens-Adu40; E. asburiae-Adu24; P. dispersa-Adu38 and P. agglomerans-Ovo3, were selected to be transformed with a plasmid, containing a sequence of genes that expresses a green fluorescent protein, when exposed to UV light. Thus, the potential of two bacterial strains that went analyzed for horizontal and vertical transfer capacity in A. darlingi was revealed. Such strains were: S. marcescens-Adu40 and P. agglomerans-Ovo3. The results of these analyzes concluded that these two strains have the potential to be used to control malaria by paratransgenesis.