title: Effective disposal of nitrogen waste in blood-fed Aedes aegypti mosquitoes requires alanine aminotransferase.
abstract: To better understand the mechanisms responsible for the success of female mosquitoes in their disposal of excess nitrogen, we investigated the role of alanine aminotransferase (ALAT) in blood-fed Aedes aegypti. Transcript and protein levels from the 2 ALAT genes were analyzed in sucrose- and blood-fed A. aegypti tissues. ALAT1 and ALAT2 exhibit distinct expression patterns in tissues during the first gonotrophic cycle. Injection of female mosquitoes with either double-stranded RNA (dsRNA)-ALAT1 or dsRNA ALAT2 significantly decreased mRNA and protein levels of ALAT1 or ALAT2 in fat body, thorax, and Malpighian tubules compared with dsRNA firefly luciferase-injected control mosquitoes. The silencing of either A. aegypti ALAT1 or ALAT2 caused unexpected phenotypes such as a delay in blood digestion, a massive accumulation of uric acid in the midgut posterior region, and a significant decrease of nitrogen waste excretion during the first 48 h after blood feeding. Concurrently, the expression of genes encoding xanthine dehydrogenase and ammonia transporter (Rhesus 50 glycoprotein) were significantly increased in tissues of both ALAT1- and ALAT2-deficient females. Moreover, perturbation of ALAT1 and ALAT2 in the female mosquitoes delayed oviposition and reduced egg production. These novel findings underscore the efficient mechanisms that blood-fed mosquitoes use to avoid ammonia toxicity and free radical damage.-Mazzalupo, S., Isoe, J., Belloni, V., Scaraffia, P. Y. Effective disposal of nitrogen waste in blood-fed Aedes aegypti mosquitoes requires alanine aminotransferase.
authors: *Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona, USA; and Department of Tropical Medicine, Vector-Borne Infectious Disease Research Center, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA.
authors: Stacy
authors: S
authors: Mazzalupo
authors: *Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona, USA; and Department of Tropical Medicine, Vector-Borne Infectious Disease Research Center, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA.
authors: Jun
authors: J
authors: Isoe
authors: *Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona, USA; and Department of Tropical Medicine, Vector-Borne Infectious Disease Research Center, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA.
authors: Virginia
authors: V
authors: Belloni
authors: *Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona, USA; and Department of Tropical Medicine, Vector-Borne Infectious Disease Research Center, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA pscaraff@tulane.edu.
authors: Patricia Y
authors: PY
authors: Scaraffia
mesh_terms: D000330:Aedes / Q000201:enzymology* / Q000235:genetics; D000410:Alanine Transaminase / Q000378:metabolism*; D000818:Animals; D004063:Digestion / Q000502:physiology; D005216:Fat Body / Q000378:metabolism*; D005260:Female; D009584:Nitrogen / Q000378:metabolism*; D012330:RNA, Double-Stranded / Q000378:metabolism
chemical_list: D012330:RNA, Double-Stranded; D000410:Alanine Transaminase; D009584:Nitrogen
keywords: RNA interference; ammonia; gene silencing; protein expression; uric acid