Interactions of iron with reactive intermediates of oxygen and nitrogen.

Iron not only functions as a cofactor for various enzymes, but it is also a source of potentially cytotoxic molecules produced through interactions with certain reactive intermediates of oxygen (ROI) and nitrogen (RNI). Protection from such iron-mediated damage results in large part from homeostatic mechanisms that regulate the sequestration of iron. Perturbations in iron homeostasis can result in an array of adverse cellular manifestations including oxidative and nitrosative stress, enhanced production of free radicals, macromolecular damage, and cell death.

Dexamethasone inhibition of the cellular immune response of Drosophila melanogaster against a parasitoid.

Host larvae of Drosophila melanogaster injected with the eicosanoid biosynthesis inhibitor, dexamethasone, prior to parasitization by the wasp Leptopilina boulardi, exhibited significantly reduced rates of melanotic encapsulation in comparison with control and saline-injected larvae. The results of this investigation suggest that prostaglandins and other eicosanoids are involved as cell-signaling molecules in the hemocytic encapsulation reaction of D. melanogaster larvae.

Resistance of the insect cell line IPLB-LdFB to salsolinol-induced apoptosis.

Apoptosis is a form of cell death that is manifested in Parkinson's disease (PD) and certain other neurodegenerative disorders. Metabolites of salsolinol (SAL), an intraneuronal, dopamine-derived tetrahydroisoquinoline (TIQ), have been shown to induce apoptosis in human dopaminergic neuroblastoma cells, implicating these molecules as causative or contributory factors in the selective killing of nigrostriatal dopaminergic neurons, a cardinal manifestation of Parkinson's disease. Since insects employ dopamine and related catecholamines in a variety of processes including cuticular sclerotization and cellular immune reactions, it was of interest to know how insect cells metabolized exogenous SAL.