title: Reactive oxygen species scavenging by catalase is important for female Lutzomyia longipalpis fecundity and mortality.
abstract: The phlebotomine sand fly Lutzomyia longipalpis is the most important vector of American visceral leishmaniasis (AVL), the disseminated and most serious form of the disease in Central and South America. In the natural environment, most female L. longipalpis are thought to survive for less than 10 days and will feed on blood only once or twice during their lifetime. Successful transmission of parasites occurs when a Leishmania-infected female sand fly feeds on a new host. Knowledge of factors affecting sand fly longevity that lead to a reduction in lifespan could result in a decrease in parasite transmission. Catalase has been found to play a major role in survival and fecundity in many insect species. It is a strong antioxidant enzyme that breaks down toxic reactive oxygen species (ROS). Ovarian catalase was found to accumulate in the developing sand fly oocyte from 12 to 48 hours after blood feeding. Catalase expression in ovaries as well as oocyte numbers was found to decrease with age. This reduction was not found in flies when fed on the antioxidant ascorbic acid in the sugar meal, a condition that increased mortality and activation of the prophenoloxidase cascade. RNA interference was used to silence catalase gene expression in female Lu. longipalpis. Depletion of catalase led to a significant increase of mortality and a reduction in the number of developing oocytes produced after blood feeding. These results demonstrate the central role that catalase and ROS play in the longevity and fecundity of phlebotomine sand flies.
authors.affiliation: Vector Group, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
authors.forename: Hector
authors.initials: H
authors.lastname: Diaz-Albiter
authors.forename: Roanna
authors.initials: R
authors.lastname: Mitford
authors.forename: Fernando A
authors.initials: FA
authors.lastname: Genta
authors.forename: Mauricio R V
authors.initials: MR
authors.lastname: Sant'Anna
authors.forename: Rod J
authors.initials: RJ
authors.lastname: Dillon
mesh_terms: D000375:Aging / Q000187:drug effects; D000595:Amino Acid Sequence; D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D002374:Catalase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005247:Feeding Behavior / Q000187:drug effects; D005260:Female; D005298:Fertility / Q000187:drug effects; D016166:Free Radical Scavengers / Q000378:metabolism*; D008969:Molecular Sequence Data; D009865:Oocytes / Q000187:drug effects / Q000201:enzymology; D011576:Psychodidae / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology*; D034622:RNA Interference / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism*; D016415:Sequence Alignment; D016019:Survival Analysis
chemical_list: D016166:Free Radical Scavengers; D017382:Reactive Oxygen Species; D002374:Catalase; D001205:Ascorbic Acid