Nitric Oxide participation in Apis mellifera hemocytic immune activation upon recognition of non-self and encapsulation

NEGRI P; M.MAGGI; LAMATTINA,L; EGUARAS M

Buenos Aires

Congreso; 45° Annual Meeting of the Society for Invertebrate Pathology.; 2012

SIP

.The honey bee Apis mellifera (Hymenoptera) is affected by many parasitosis representing a serious threat to our ecosystem and apiculture. Studing A. mellifera immune system contributes with rewarding information for developing new strategies to confront honey bee diseases. Elimination of organisms into the insect hemocoel requires that blood cells (hemocytes) recognize and respond to the invader. Up to date the data concerning cellular immune responses of A. mellifera is scarce. After recognition of non-self, hemocytes ?spread?. If the foreign agent is small, this spreading promotes phagocytosis, whereas a larger object triggers an encapsulation response. Hemocyte spreading in response to biotic (bacterial elicitors) and abiotic (plastic or glass) surfaces is measure of immune activation. Nitric oxide (NO) is a signaling and immune effector molecule synthesized by the enzyme nitric oxide synthase (NOS). In insects, NO production has been reported in response to microbial infection in several species of lepidopterans, hemipterans, and dipterans. In this work we studied the participation of NO in the hemocytic responses of A. mellifera upon recognition of non-self and encapsulation in-vitro. Experiments were conducted over primary cultures of A. mellifera spinning larvae and one-day-old workers hemocytes. Flagellin treatments enhanced A. mellifera hemocytes spreading and NO production in an L-arginine dependent process. Glass adherent hemocytes produced great amounts of NO. When treated with the NO scavenger cPTIO, hemocyte spreading over glass surfaces was reduced. Our results suggest that NO participates in A. mellifera immune response to non-self and at the beginning of an encapsulation response in honey bees. Oral exposition