title: Trypsin inhibitor from Leucaena leucocephala seeds delays and disrupts the development of Aedes aegypti, a multiple-disease vector.
abstract: BACKGROUND
  Nowadays, the Aedes aegypti mosquito represents a serious public health issue in view of the large outbreaks of the arboviral diseases zika, dengue, chikungunya and yellow fever. This holometabolous insect has midgut digestive enzymes that are trypsin- and chymotrypsin-like proteins. Protease inhibitors are able to bind to proteolytic enzymes and promote a blockage in digestion and nutrition, leading to death. Thus, we investigated the effect of trypsin inhibitor of Leucaena leucocephala (LTI) seeds on egg hatching, larval development and digestive midgut proteases.
  
  
  RESULTS
  LTI was obtained by trichloroacetic acid precipitation followed by a single chromatography step on anhydrous trypsin sepharose. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate showed a single protein band with a molecular mass close to 20 kDa. After exposure of Ae. aegypti eggs to LTI (0.3 mg mL-1), egg hatching was reduced (50%). LTI did not show acute toxicity on newly hatched larvae incubated under the same conditions, but after 10 days of exposure a high mortality rate (86%) was observed and the surviving larvae had a 25% delay in development. LTI was able to inhibit in vitro the midgut enzymatic activity (70%), and when larvae were incubated with LTI solution we observed an inhibition of 56%.
  
  
  CONCLUSIONS
  LTI is a promising new tool to control critical points of Ae. aegypti development. © 2016 Society of Chemical Industry.
authors.affiliation: Biochemistry and Molecular Biology Department, Federal University of Ceará, Fortaleza, Ceará, Brazil.
authors.forename: Luiz Cp
authors.initials: LC
authors.lastname: Almeida Filho
authors.affiliation: Biochemistry and Molecular Biology Department, Federal University of Ceará, Fortaleza, Ceará, Brazil.
authors.forename: Terezinha M
authors.initials: TM
authors.lastname: de Souza
authors.affiliation: Biology Department, Federal University of Ceará, Fortaleza, Ceará, Brazil.
authors.forename: Pedro Ms
authors.initials: PM
authors.lastname: Tabosa
authors.affiliation: Biology Department, Federal University of Ceará, Fortaleza, Ceará, Brazil.
authors.forename: Nayana G
authors.initials: NG
authors.lastname: Soares
authors.affiliation: Biochemistry and Molecular Biology Department, Federal University of Ceará, Fortaleza, Ceará, Brazil.
authors.forename: Lady Cb
authors.initials: LC
authors.lastname: Rocha-Bezerra
authors.affiliation: Biochemistry and Molecular Biology Department, Federal University of Ceará, Fortaleza, Ceará, Brazil.
authors.forename: Ilka M
authors.initials: IM
authors.lastname: Vasconcelos
authors.affiliation: Biology Department, Federal University of Ceará, Fortaleza, Ceará, Brazil.
authors.forename: Ana Fu
authors.initials: AF
authors.lastname: Carvalho
mesh_terms: D000330:Aedes / Q000187:drug effects* / Q000254:growth & development; D000818:Animals; D007887:Fabaceae / Q000737:chemistry*; D007303:Insect Vectors / Q000187:drug effects; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D010063:Ovum / Q000187:drug effects / Q000254:growth & development; D010572:Pest Control, Biological / Q000379:methods*; D012639:Seeds / Q000737:chemistry; D014361:Trypsin Inhibitors / Q000494:pharmacology*
chemical_list: D014361:Trypsin Inhibitors
keywords: Leucaena; dengue; legume seeds; midgut enzymes; protease inhibitors; zika