Apis mellifera hemocytes generate increased amounts of nitric oxide in response to wounding/encapsulation

Abstract

Apis mellifera populations are being threatened by several pathogens and parasitosis. Several authors have proposed that honey bee colonies may suffer from a compromised immune system leading to colony loss. This is why the study of A. mellifera immune system has become a topic of pressing concern. Nitric oxide (NO) is a signaling and immune effector molecule that has been proposed as a key molecule in invertebrate immunity, and that plays a part in A. mellifera cellular defenses. This paper deals with NO participation in the response to wounding/encapsulation challenge in A. mellifera fifth instar (L5) larvae. Challenging A. mellifera L5 larvae with nylon implants enhanced NO production and spreading in granulocyte-like hemocytes and increased the number of this NO-producing hemocyte type. However, AmNOS expression levels were not influenced by the insult. These results reveal that NO participates in the wound healing/encapsulation response as a signal molecule, possibly by the activation of a constitutively expressed AmNOS in honey bees.