Aedes aegypti midgut remodeling during metamorphosis

Abstract

The Aedes aegypti midgut is restructured during metamorphosis; its epithelium is renewed by replacing the digestive and endocrine cells through stem or regenerative cell differentiation. Shortly after pupation (white pupae) begins, the larval digestive cells are histolized and show signs of degeneration, such as autophagic vacuoles and disintegrating microvilli. Simultaneously, differentiating cells derived from larval stem cells form an electron-dense layer that is visible 24h after pupation begins. Forty-eight hours after pupation onset, the differentiating cells yield an electron-lucent cytoplasm rich in microvilli and organelles. Dividing stem cells were observed in the fourth instar larvae and during the first 24h of pupation, which suggests that stem cells proliferate at the end of the larval period and during pupation. This study discusses various aspects of the changes during midgut remodeling for pupating A. aegypti.

Imidacloprid impairs the post‐embryonic development of the midgut in the yellow fever mosquito Stegomyia aegypti (=Aedes aegypti)

“…The degeneration of digestive cells begins at the end of the L4 stage and ends 18 h after pupation (Nishiura et al, 2003;Ray et al, 2007). Because the digestive cells of the L4 and WP stages are typically in the process of cell death (Ray et al, 2007;Fernandes et al, 2014), it was not possible to identify the effects of imidacloprid in larval digestive cells during these stages. In P24 control individuals, many differentiating cells were present, giving rise to new digestive cells (Nishiura et al, 2003;Ray et al, 2007;Fernandes et al, 2014).…”

“…Interestingly, endocrine (FMRF-positive) cells were present in all stages of St. aegypti development; however, these cells were localized to the posterior region of the midgut (Moffett & Moffett, 2005). Similar to digestive cells, endocrine cells originate through the differentiation of regenerative cells (Ohlstein & Spradling, 2006), which presumably appear de novo from the P24 stage (Fernandes et al, 2014). However, the number of endocrine cells in L4 individuals treated with imidacloprid was higher than that of the control, and the endocrine cells were localized in the anterior midgut.…”

“…The midguts of St. aegypti begin remodelling in the late larval stage with the death of the digestive cells; this process continues for up to18 h after pupation (Nishiura & Smouse, 2002;Nishiura et al, 2003). Therefore, to study the effects of imidacloprid in the cell genome, we examined DNA fragmentation as indicative of cell death in P24 and P48, phases in which the regenerative cells are differentiating (Ray et al, 2007;Fernandes et al, 2014).…”

Effects of Achyranthes aspera Extracts on the Survival and Midgut Histo-architecture of Aedes aegypti L. Early IV Instars

“…aegypti larvae and new cells are formed replacing old ones [12]. Consequently, the lethal effects of phytochemicals on the midgut tissues may affect growth and development adversely [13,14].…”

Proteomic analysis of Aedes aegypti midgut during post-embryonic development and of the female mosquitoes fed different diets

“…The midgut remodeling during metamorphosis includes the replacement of digestive cells in the larval epithelium during pupation by the digestive cells of the adult. These changes allow the insect to change its diet and it ceases to feed on microorganisms and decomposing detritus and begins to feed on plant sugars and/or blood [7][8][9]. In this study, protein profiles of the A. aegypti midgut in the larval, pupal, and adult stages (newly emerged and fed with sugar or blood) were studied.…”