Peroxidase isozymes from winter wheat (Triticum aestivum L. cv Orso) seedlings extracts showed phenoloxidase-like activity, becoming visible on polyacrylamide gels also in the absence of hydrogen peroxide. The results obtained after a characterization of the two activities, based on their substrate specificity, on their selective inhibition, and on the possible occurrence of artifacts, suggeste...

Two closely related copper proteins, phenoloxidase and haemocyanin, are known to be involved in different physiological functions such as the primary immune response and oxygen transport. Although the proteins differ structurally, they have the same active site by which dioxygen is bound. Recent results reveal that haemocyanin also exhibits phenoloxidase activity. A scenario is proposed for the...

To improve thermoregulation in colder environments, insects are expected to darken their cuticles with melanin via the phenoloxidase cascade, a phenomenon predicted by the thermal melanin hypothesis. However, the phenoloxidase cascade also plays a significant role in insect immunity, leading to the additional hypothesis that the thermal environment indirectly shapes immune function via direct s...

Ecological immunology is an interdisciplinary field that helps elucidate interactions between the environment and immune response. The host species individuals experience have profound effects on immune response in many species of insects. However, this conclusion comes from studies of herbivorous insects even though species of mycophagous insects also inhabit many different host species. The g...

In this study, we tested the effects of dietary nickel on the activity of glutathione S-transferase (GST), esterases, phenoloxidase, and encapsulation in the haemolymph of larvae of the greater wax moth Galleria mellonella. We also explored the effects of dietary nickel on larval resistance to infection by the fungus Beauveria bassiana. Larvae fed a low dose of nickel (10 μg g(-1)) had signific...

Eggs of the parasitoid Leptopilina boulardi, strain L104, are routinely encapsulated by haemocytes in C’rosophila melanogaster larvae, and the capsules subsequently melanize. In D. melanogaster mutant strains deficient for phenoloxidase activity, L104 eggs are encapsulated by host haemocytes but the cellular capsules do not melanize and harden. These observations suggest that phenoloxidases are...

/V-/j-Alanyldopamine (NBAD) has attracted a great deal of interest because of its significance in catecholamine metabolism in insects with which phenoloxidase is concerned.1' Kramer et al. synthesized NBADby coupling the acid component of /V-/?-alanine with the amine component of dopamine in aqueous solution.2' Their method, however, required several chromatographic steps to purify the syntheti...