title: Effect of Moringa oleifera lectins on survival and enzyme activities of Aedes aegypti larvae susceptible and resistant to organophosphate.
abstract: The indiscriminate use of synthetic insecticides to control Aedes aegypti has led to emergence of resistant populations. Moringa oleifera seeds contain the lectins WSMoL and cMoL. WSMoL has larvicidal activity on fourth-stage of A. aegypti organophosphate-susceptible larvae (Rockefeller L4). This study reports on the effects of cMoL on the survival of Rockefeller L4 as well as of WSMoL and cMoL on L4 from an organophosphate-resistant population (Rec-R). The effects of lectins on digestive (amylase, trypsin, and protease) and detoxifying (superoxide dismutase (SOD), α- and β-esterases) enzymes from larvae were also determined. cMoL (0.1-0.8 mg/ml) did not kill Rockefeller L4 as well as WSMoL and cMoL (0.1-0.8 mg/ml) were not larvicidal for Rec-R L4. WSMoL stimulated protease, trypsin-like, and α-amylase from Rockefeller L4 while cMoL inhibited these enzymes. WSMoL had no effect on trypsin-like activity from Rec-R L4 but inhibited protease and α-amylase. Among digestive enzymes of Rec-R L4, cMoL inhibited only trypsin-like activity. cMoL inhibited SOD activities from Rockefeller and Rec-R L4 in a higher level than WSMoL while β-esterase from Rockefeller L4 was more inhibited by WSMoL. The lectins promoted low stimulation or inhibition of α-esterase activities from both populations. In conclusion, Rockefeller and Rec-R larvae were distinctly affected by M. oleifera lectins, and larvicidal mechanism of WSMoL on Rockefeller L4 may involve deregulation of digestive enzymes. cMoL interfered mainly on SOD activity and thus it can be investigated as a synergistic agent for controlling populations whose resistance is linked to an increased detoxifying process mediated by this enzyme.
authors.affiliation: Departamento de Bioquímica, CCB, Universidade Federal de Pernambuco, Cidade Universitária, 50670-420, Recife, Pernambuco, Brazil.
authors.forename: Afonso Cordeiro
authors.initials: AC
authors.lastname: Agra-Neto
authors.forename: Thiago Henrique
authors.initials: TH
authors.lastname: Napoleão
authors.forename: Emmanuel Viana
authors.initials: EV
authors.lastname: Pontual
authors.forename: Nataly Diniz de Lima
authors.initials: ND
authors.lastname: Santos
authors.forename: Luciana de Andrade
authors.initials: Lde A
authors.lastname: Luz
authors.forename: Cláudia Maria Fontes
authors.initials: CM
authors.lastname: de Oliveira
authors.forename: Maria Alice Varjal
authors.initials: MA
authors.lastname: de Melo-Santos
authors.forename: Luana Cassandra Breitenbach Barroso
authors.initials: LC
authors.lastname: Coelho
authors.forename: Daniela Maria do Amaral Ferraz
authors.initials: DM
authors.lastname: Navarro
authors.forename: Patrícia Maria Guedes
authors.initials: PM
authors.lastname: Paiva
mesh_terms: D000330:Aedes / Q000187:drug effects* / Q000201:enzymology; D000818:Animals; D004950:Esterases / Q000378:metabolism; D007305:Insecticide Resistance; D007306:Insecticides; D007814:Larva / Q000187:drug effects / Q000201:enzymology; D029588:Moringa oleifera / Q000737:chemistry*; D010755:Organophosphates; D010936:Plant Extracts / Q000494:pharmacology; D037121:Plant Lectins / Q000494:pharmacology*; D012639:Seeds / Q000737:chemistry; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D007306:Insecticides; D010755:Organophosphates; D010936:Plant Extracts; D037121:Plant Lectins; D013482:Superoxide Dismutase; D004950:Esterases