Effect of cyanobacteria on the development of Culex quinquefasciatus mosquito larvae

CUNIOLO, ANTONELLA; MARTIN, MARÍA V; BERÓN, CORINA M.

Mar del Plata

Congreso; XVIII Congreso de la Sociedad Argentina de Microbiología General; 2023

SAMIGE

Cyanobacteria are globally widespread and have the ability to synthesize a diverse range of bioactive compounds under optimal growth conditions. Some of these compounds differ from those synthesized by the same organisms under environmental stress conditions and could be useful in regulating the growth of mosquito populations. Some mosquito species are vectors of diseases such as malaria, dengue fever, yellow fever, West Nile fever, and some encephalitis. These insects are widespread throughout the world, and controlling their population density is often the only means available to prevent and control outbreaks of these diseases. The objective of this work was to analyze the impact of cyanobacteria, which are killed through a recently described regulated process, on the larval stages of two isolines of Culex quinquefasciatus mosquitoes. For this purpose, some strains of model and native cyanobacteria were treated under different conditions, and an aliquot of each culture was provided to gravid females as oviposition sites. Moreover, interaction assays were conducted to assess how second-stage larvae responded to different extracts of treated cyanobacteria, and the effects of these cyanobacteria on larval development and/or mortality were analyzed. Furthermore, lipid peroxidation was analyzed in larval tissue using Schiff’s reagent, which detects aldehydes that originate from lipid peroxides in stressful conditions. Oxidative damage was detected with colorimetric stains such as DAB (3,3'- diaminobenzidine) for peroxide production. Finally, to investigate a potential mechanism of death, mosquito larvae were fed with canonical inhibitors of specific regulated cell death pathways. The results performed showed no differences in preference for oviposition sites. However, differential effects on the morphology, development, and/or mortality of larvae exposed to treated cyanobacteria, which undergo death through a specific regulated process were detected. This observation suggests that the bioactive compounds released by cyanobacteria could be potential molecules to manage mosquito populations. Effects on larval morphology, development, and/or mortality can be reversed by canonical inhibitors of regulated cell death. In summary, some cyanobacteria strains have shown potential effects for the control of mosquito populations as a way of preventing and controlling outbreaks of diseases vectorized by these insects. The cyanobacteria used in the study has also been shown to alter the growth of aquatic plants such as Lemna sp. in open environments without being harmful, demonstrating the feasibility of its use in both artificial and natural mosquito breeding areas. Further research is needed to analyze the use of bioactive compounds from cyanobacteria in strategies to control mosquito vector populations.