title: Yolk hydrolases in the eggs of Anticarsia gemmatalis hubner (Lepidoptera: Noctuidae): a role for inorganic polyphosphate towards yolk mobilization.
abstract: Despite being the main insect pest on soybean crops in the Americas, very few studies have approached the general biology of the lepidopteran Anticarsia gemmatalis and there is a paucity of studies with embryo formation and yolk mobilization in this species. In the present work, we identified an acid phosphatase activity in the eggs of A. gemmatalis (agAP) that we further characterized by means of biochemistry and cell biology experiments. By testing several candidate substrates, this enzyme proved chiefly active with phosphotyrosine; in vitro assays suggested a link between agAP activity and dephosphorylation of egg yolk phosphotyrosine. We also detected strong activity with endogenous and exogenous short chain polyphosphates (PolyP), which are polymers of phosphate residues involved in a number of physiological processes. Both agAP activity and PolyP were shown to initially concentrate in small vesicles clearly distinct from typically larger yolk granules, suggesting subcellular compartmentalization. As PolyP has been implicated in inhibition of yolk proteases, we performed in vitro enzymatic assays with a cysteine protease to test whether it would be inhibited by PolyP. This cysteine protease is prominent in Anticarsia egg homogenates. Accordingly, short chain PolyP was a potent inhibitor of cysteine protease. We thereby suggest that PolyP hydrolysis by agAP is a triggering mechanism of yolk mobilization in A. gemmatalis.
authors.affiliation: Laboratório de Entomologia Médica, Programa de Parasitologia e Biologia Celular, Instituto de Biofísica Carlos Chagas Filho (IBCCF), Centro de Ciências da Saúde (CCS), Universidade Federal do Rio de Janeiro (UFRJ), Cidade Universitária, Rio de Janeiro CEP 21941-590, RJ, Brazil; Departamento de Bioquímica, Instituto de Química, Centro de Ciências da Matemática e Natureza, UFRJ, Cidade Universitária, Rio de Janeiro CEP 21941-909, RJ, Brazil.
authors.forename: Danielle M P
authors.initials: DM
authors.lastname: Oliveira
authors.forename: Fabio M
authors.initials: FM
authors.lastname: Gomes
authors.forename: Danielle B
authors.initials: DB
authors.lastname: Carvalho
authors.forename: Isabela
authors.initials: I
authors.lastname: Ramos
authors.forename: Alan B
authors.initials: AB
authors.lastname: Carneiro
authors.forename: Mario A C
authors.initials: MA
authors.lastname: Silva-Neto
authors.forename: Wanderley
authors.initials: W
authors.lastname: de Souza
authors.forename: Ana P C A
authors.initials: AP
authors.lastname: Lima
authors.forename: Kildare
authors.initials: K
authors.lastname: Miranda
authors.forename: Ednildo A
authors.initials: EA
authors.lastname: Machado
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism*; D000818:Animals; D004530:Egg Yolk / Q000378:metabolism*; D047108:Embryonic Development; D009036:Moths / Q000201:enzymology*; D011122:Polyphosphates / Q000378:metabolism; D059748:Proteolysis
chemical_list: D011122:Polyphosphates; D000135:Acid Phosphatase
keywords: Acid phosphatase; Pest insect; Polyphosphate; Protease; Yolk degradation