Silva Lilian N D, Ribeiro-Neto José A, Valadares Jéssica M M, Costa Mariana M, Lima Luciana A R S, Grillo Luciano A M, Cortes Vanessa F, Santos Herica L, Alves Stênio N, Barbosa Leandro A
Laboratório de Bioquímica Celular, Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindu, Av Sebastião Gonçalves Coelho 400, Bairro Chanadour, Divinópolis, MG, CEP 35501-296, Brazil.
Laboratório de Insetos Vetores de Doenças, Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindu, Av Sebastião Gonçalves Coelho 400, Divinópolis, MG, 35501-296, Brazil.
J Membr Biol. 2016 Aug;249(4):459-67. doi: 10.1007/s00232-016-9886-1. Epub 2016 Mar 18.
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.
致倦库蚊是淋巴丝虫病的主要传播媒介，防治这种昆虫对公众健康至关重要。有报道称，昆虫对目前用于控制这种传播媒介的产品产生了抗性，因此，对新产品的研发力度加大。在本研究中，我们评估了对致倦库蚊具有杀幼虫活性的脂肪酸甲酯（FAMEs）对蚊幼虫葡萄糖、总蛋白和三酰甘油含量以及Na(+)/K(+)-ATP酶活性的影响。将四龄幼虫暴露于这些化合物中会导致总蛋白含量降低以及Na(+)/K(+)-ATP酶活性增加。此外，还在纯化的猪肾Na(+)/K(+)-ATP酶膜、红细胞血影膜和幼虫膜制剂上评估了FAMEs对细胞膜的直接作用。在对幼虫膜制剂进行20分钟的FAMEs处理后，未发现总磷脂和胆固醇含量有变化，但只有360μg/mL的FAME 2能够降低红细胞血影膜的总磷脂含量。此外，只有60和360μg/mL的FAME 3能激活纯化的Na(+)/K(+)-ATP酶，这与FAMEs处理幼虫膜制剂的效果相反，并导致泵活性受到抑制。这些数据共同表明，FAMEs可能通过这种机制调节完整幼虫上的Na(+)/K(+)-ATP酶，而不是直接作用，因为FAMEs在膜制剂中的直接作用降低了Na(+)/K(+)-ATP酶的活性。这些化合物引起的生化变化是显著的，可能会对致倦库蚊幼虫的发育和存活产生负面影响。
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