The Influence of Fatty Acid Methyl Esters (FAMEs) in the Biochemistry and the Na+/K+-ATPase Activity of Culex quinquefasciatus Larvae

Abstract

Culex quinquefasciatus is the main vector of lymphatic filariasis and combating this insect is of great importance to public health. There are reports of insects that are resistant to the products currently used to control this vector, and therefore, the search for new products has increased. In the present study, we have evaluated the effects of fatty acid methyl esters (FAMEs) that showed larvicidal activity against C. quinquefasciatus, on glucose, total protein, and triacylglycerol contents and Na(+)/K(+)-ATPase activity in mosquito larvae. The exposure of the fourth instar larvae to the compounds caused a decrease in the total protein content and an increase in the activity of the Na(+)/K(+)-ATPase. Furthermore, the direct effect of FAMEs on cell membrane was assessed on purified pig kidney Na(+)/K(+)-ATPase membranes, erythrocyte ghost membranes, and larvae membrane preparation. No modifications on total phospholipids and cholesterol content were found after FAMEs 20 min treatment on larvae membrane preparation, but only 360 µg/mL FAME 2 was able to decrease total phospholipid of erythrocyte ghost membrane. Moreover, only 60 and 360 µg/mL FAME 3 caused an activation of purified Na(+)/K(+)-ATPase, that was an opposite effect of FAMEs treatment in larvae membrane preparation, and caused an inhibition of the pump activity. These data together suggest that maybe FAMEs can modulate the Na(+)/K(+)-ATPase on intact larvae for such mechanisms and not for a direct effect, one time that the direct effect of FAMEs in membrane preparation decreased the activity of Na(+)/K(+)-ATPase. The biochemical changes caused by the compounds were significant and may negatively influence the development and survival of C. quinquefasciatus larvae.

Protein kinase C mediates juvenile hormone–dependent phosphorylation of Na+/K+-ATPase to induce ovarian follicular patency for yolk protein uptake

“…Recent studies have illustrated the function of Na ϩ /K ϩ -ATPase in osmoregulation of crustaceans, neurological cancers, and therapeutic targets for diseases (18 -20). Na ϩ /K ϩ -ATPase is also reported as an efficient target of insecticides (21,22). Whereas extensive studies have been carried out to elucidate the function of Na ϩ / K ϩ -ATPase in controlling the ion transport through cell membranes, the regulatory cascade of Na ϩ /K ϩ -ATPase activity in JH-dependent initiation of patency has been lacking.…”

Evaluation of the chemical defense fluids of Macrotermes carbonarius and Globitermes sulphureus as possible household repellents and insecticides

“…The insecticidal activity of this extract was contributed to by octadecanoic acid and stearic acid, leading to a low LC 50 of this extract (16.92 mg/ml), as inferred in a previous study. A study described in 72 proved that a formulation of fatty acid methyl ester (FAME) that consists of methyl stearate showed larvicidal activity against C. quinquefasciatus. The previous study showed that the insecticidal activity of this compound occurred through ingestion, which is in consistent with and validated the result of the present study.…”

Crude extract of the tropical tree Gallesia integrifolia (Phytolaccaceae) for the control of Aedes aegypti (Diptera: Culicidae) larvae

“…The fatty acids found in the leaves are responsible for controlling water loss to the environment during gas exchanges, and protect the plant against the nutrient loss due to the high incidence of ultraviolet rays and intense rainfall (Kozlowski & Pallardy, 1996); in the flowers, as well as in the leaves, the fatty acids are part of the surface impermeabilization, avoiding water loss, and part of the pollination process as they are in the chemical composition of flower nectar (Levin, McCue, & Davidowitz, 2017) whereas, in the fruits and seeds, these acids act as a barrier to moist diffusion, as a form of protection, because it is a reserve organ to the embryo (Esau, 1986;Kunst & Samuels, 2009). In general, fatty acids act on the cellular structure of vegetables, growth, nutrition, senescence, and protection against phytopathogens and the environment (Meï et al, 2015;Li, Xu, Li-Beisson, & Philippar, 2016;Silva et al, 2016).…”

“…The linoleic acid ethyl ester as well as the linolenic acid methyl ester are present in the dark green leaves because they are part of the apolar lipid fraction of plants (Simopoulos, 2002). There are no reports on the activity of these molecules against A. aegypti, but fatty acid methyl ester had LC 99.9 of 0.17 mg/mL in Culex quinquefasciatus larvae (Silva et al, 2016), indicating insecticide effect against larvae of this insect.…”