Maintenance of redox balance by antioxidants in hemolymph of the greater wax moth Galleria mellonella larvae during encapsulation response

Abstract

The lipid peroxidation process in hemocytes, activities of phenoloxidase and key enzymatic antioxidants (superoxide dismutase, glutathione-S-transferase, catalase) and nonenzymatic antioxidants (thiols, ascorbate) in hemolymph of the greater wax moth Galleria mellonella L. (Lepidoptera: Pyralidae) were studied during the encapsulation process of nylon implants. It has been established that as soon as 15 min after piercing a cuticle with the implant, a capsule is formed on its surface. Active melanization of the capsule has been shown to last for 4 h. During the first hours after incorporating the implant, an increase in phenoloxidase activity and lipid peroxidation in the insect hemocytes has been revealed. Adhesion and degranulation on the surface of foreign object lead to the depletion of total hemocytes count (THC). Our results indicated that thiols and ascorbate molecules take part in the immediate antioxidant response, during later stages of encapsulation process hemolymph glutathione-S-transferase detoxifies and protects insect organism thereby restoring the internal redox balance. We suggest that nonenzymatic and enzymatic antioxidants of hemolymph plasma play a key role in the maintenance of redox balance during encapsulation of foreign targets.

Recent Advances in the Use of Galleria mellonella Model to Study Immune Responses against Human Pathogens

“…In this process, granular cells recognize large foreign bodies such as protozoa, nematodes and parasitic insect eggs or larvae in the hemolymph, promoting plasmacyte binding (Figure 2B). A smooth capsule is formed, composed of superimposed cells [76,77,78]. When capsule formation begins, the number of hemocytes circulating in the hemolymph decreases as they are used in this process.…”

“…When capsule formation begins, the number of hemocytes circulating in the hemolymph decreases as they are used in this process. After capsule formation, an increase of hemocytes with enzymatic activity occurs [78]. Encapsulation and nodulation can also occur when phagocytosis fails to eliminate pathogens [79], moreover, the type of response will be determined by pathogen characteristics and concentration.…”

Establishment of an induced memory response in Pseudomonas aeruginosa during infection of a eukaryotic host

“…We therefore passaged the P. aeruginosa clinical isolate multiple times in larvae of the wax moth Galleria mellonella. The immune system of the G. mellonella larvae shows functional similarities to human innate immune responses such as expression of antimicrobial peptides, lysozyme, generation of reactive oxygen species, and phagocytosis of invading microbes [23][24][25][26].…”

Superoxide dismutase from venom of the ectoparasitoid Scleroderma guani inhibits melanization of hemolymph

“…Interestingly, SguaSOD3 was able to inhibit the PO activity in hemolymph of the host in a dose‐dependent manner, like SOD3 in venom of L. boulardi (Colinet et al, ). It is known that several enzymatic antioxidants including SOD are involved in the regulation of the process of melanogenesis by balancing the generation of ROS during melanization (Brivio, Mastore, & Pagani, ; Grizanova et al, ). As suggested by Colinet et al (), host melanization pathway would be interfered by SOD3 through dismutation of the superoxide anion, implying a unique mechanism of disturbing PPO cascade.…”

“…| 9 of 12 SOD are involved in the regulation of the process of melanogenesis by balancing the generation of ROS during melanization (Brivio, Mastore, & Pagani, 2005;Grizanova et al, 2018). As suggested by Colinet et al (2011), host melanization pathway would be interfered by SOD3 through dismutation of the superoxide anion, implying a unique mechanism of disturbing PPO cascade.…”