Ultrastructural Studies of Magonia pubescens (St. Hil.) Extract Toxicity in the Midgut of Aedes aegypti (L.) (Diptera: Culicidae) Larvae

Abstract

The toxicity effects of the crude ethanol extract (c.e.e.), from the peel of the stem
of Magonia pubescens (St. Hil.), in the mesentery cells of larvae of the Aedes
aegypti mosquito at the 3rd stage (L.) (Diptera: Culicidae), were investigated with
electronic microscopy. Several periods of exposure to c.e.e. were analyzed and
different destruction degrees were observed in agreement with increasing of time
of exposure. The morphologic alterations began after 4h of treatment and they
included the loss of mitochondrial cristae and the thickening of the peritrophic
matrix. As the period of exposure increased, new ultrastructural alterations were
evidenced, standing out the complete mitochondria destruction, the increase in
the number of vacuoles, the loss, reduction or breakage of the microvilli and some
nuclear alterations, proving the high toxicity of c.e.e. and effectiveness in the control
of larvae of the A. aegypti.