title: A mitochondrial exopolyphosphatase activity modulated by phosphate demand in Rhipicephalus (Boophilus) microplus embryo.
abstract: This study describes Exopolyphosphatases (PPX) activity in mitochondria of Rhipicephalus microplus embryos. Mitochondria were isolated by differential centrifugation and PPX activity was analyzed through the hydrolysis of the substrate Polyphosphate (Poly P(15)). We investigated the influence of NADH, NAD+, Pi and ADP in a concentration range of 0.1-2.0 mM. Poly P hydrolysis was stimulated about two-fold by NADH and strongly inhibited by Pi. The PPX activity also increased in the presence of the respiratory substrates pyruvic and succinic acids, and this stimulatory effect disappeared upon addition of KCN. Mitochondrial respiration was activated by ADP using poly P as the only source of Pi. Endogenous poly P content changed following PPX activity during embryogenesis from the first up to 18th day of development. The data describe exopoly P as being modulated by Pi demand and related to energy supply during embryogenesis of hard ticks.
authors.affiliation: Laboratório de Química e Função de Proteínas e Peptídeos and Laboratório de Biologia Celular e Tecidual-CBB-UENF, Avenida Alberto Lamego 2000, Horto, CEP 28015-620 Campos dos Goytacazes, RJ, Brazil.
authors.forename: Eldo
authors.initials: E
authors.lastname: Campos
authors.forename: Arnoldo
authors.initials: A
authors.lastname: Façanha
authors.forename: Jorge
authors.initials: J
authors.lastname: Moraes
authors.forename: Itabajara
authors.initials: I
authors.lastname: da Silva Vaz
authors.forename: Aoi
authors.initials: A
authors.lastname: Masuda
authors.forename: Carlos
authors.initials: C
authors.lastname: Logullo
mesh_terms: D017766:Acid Anhydride Hydrolases / Q000378:metabolism*; D000818:Animals; D002458:Cell Fractionation; D019069:Cell Respiration; D004625:Embryo, Nonmammalian / Q000201:enzymology; D047108:Embryonic Development; D019476:Insect Proteins / Q000378:metabolism*; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000378:metabolism*; D011122:Polyphosphates / Q000378:metabolism*; D048494:Rhipicephalus / Q000196:embryology* / Q000201:enzymology