title: Midgut morphological changes and autophagy during metamorphosis in sand flies.
abstract: During metamorphosis, holometabolous insects undergo significant remodeling of their midgut and become able to cope with changes in dietary requirements between larval and adult stages. At this stage, insects must be able to manage and recycle available food resources in order to develop fully into adults, especially when no nutrients are acquired from the environment. Autophagy has been previously suggested to play a crucial role during metamorphosis of the mosquito. Here, we investigate the overall morphological changes of the midgut of the sand fly during metamorphosis and assess the expression profiles of the autophagy-related genes ATG1, ATG6, and ATG8, which are associated with various steps of the autophagic process. Morphological changes in the midgut start during the fourth larval instar, with epithelial degeneration followed by remodeling via the differentiation of regenerative cells in pre-pupal and pupal stages. The changes in the midgut epithelium are paired with the up-regulation of ATG1, ATG6 and ATG8 during the larva-adult transition. Vein, a putative epidermal growth factor involved in regulating epithelial midgut regeneration, is also up-regulated. Autophagy has further been confirmed in sand flies via the presence of autophagosomes residing within the cytoplasmic compartment of the pupal stages. An understanding of the underlying mechanisms of this process should aid the future management of this neglected tropical vector.
authors.affiliation: Departamento de Biologia Geral, Universidade Federal de Viçosa (DBG/UFV), Campus Universitário, Viçosa, Minas Gerais, CEP 36570-900, Brazil.
authors.forename: Juliana
authors.initials: J
authors.lastname: Malta
authors.affiliation: Department of Entomology, Kansas State University (KSU), Manhattan, KS 66506, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Heerman
authors.affiliation: Department of Entomology, Kansas State University (KSU), Manhattan, KS 66506, USA.
authors.forename: Ju Lin
authors.initials: JL
authors.lastname: Weng
authors.affiliation: Departamento de Biologia Geral, Universidade Federal de Viçosa (DBG/UFV), Campus Universitário, Viçosa, Minas Gerais, CEP 36570-900, Brazil.|Departamento de Entomologia, Universidade Federal de Viçosa (DBG/UFV), Campus Universitário, Viçosa, Minas Gerais, CEP 36570-900, Brazil.
authors.forename: Kenner M
authors.initials: KM
authors.lastname: Fernandes
authors.affiliation: Departamento de Biologia Geral, Universidade Federal de Viçosa (DBG/UFV), Campus Universitário, Viçosa, Minas Gerais, CEP 36570-900, Brazil.
authors.forename: Gustavo Ferreira
authors.initials: GF
authors.lastname: Martins
authors.affiliation: Department of Entomology, Kansas State University (KSU), Manhattan, KS 66506, USA. mrortigao@gmail.com.|Departamento de Entomologia, Universidade Federal de Viçosa (DBG/UFV), Campus Universitário, Viçosa, Minas Gerais, CEP 36570-900, Brazil. mrortigao@gmail.com.|Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences (USUHS), Bethesda, MD 20814, USA. mrortigao@gmail.com.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Ramalho-Ortigão
mesh_terms: D000818:Animals; D001343:Autophagy / Q000235:genetics; D004064:Digestive System / Q000033:anatomy & histology / Q000196:embryology / Q000648:ultrastructure; D005260:Female; D017344:Genes, Insect; D008675:Metamorphosis, Biological; D011576:Psychodidae / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development* / Q000648:ultrastructure; D011679:Pupa / Q000648:ultrastructure
keywords: Autophagy; Ecdysone; Metamorphosis; Midgut development; Sand flies