or quinolinic acid (or both). The modifying gene has no demonstrable effect on the utilization of exogenously supplied nicotinamide (K. Nakamura and C. S. Gowans, Genetics 51:931, 1965). Two observations strongly indicate that the modifying gene does not operate through a modification of the pathway of synthesis of niacin. First, the nicotinamide auxotrophs carrying the modifying gene grow norm...

Yeasts utilize tryptophan for the synthesis of nicotinic acid under aerobic, but not under anaerobic, conditions. Under aerobic conditions of growth, radioactivity from tryptophanJ4C uniformly labeled in the benzene ring and 14C!-carboxyl-labeled 3-hydroxyanthranilic acid is incorporated into nicotinic acid. Under anaerobic conditions, little radioactivity from these compounds is incorporated i...

Quinolinic acid (2,3-pyridinedicarboxylic acid, QUIN) is a well-known neurotoxin. Consequently, QUIN could produce reactive oxygen species (ROS). ROS are generated in reactions catalyzed by transition metals, especially iron (Fe). QUIN can form coordination complexes with iron. A combination of differential pulse voltammetry, deoxyribose degradation and Fe(II) autoxidation assays was used for e...

Yeasts utilize tryptophan for the synthesis of nicotinic acid under aerobic, but not under anaerobic, conditions. Under aerobic conditions of growth, radioactivity from tryptophanJ4C uniformly labeled in the benzene ring and 14C!-carboxyl-labeled 3-hydroxyanthranilic acid is incorporated into nicotinic acid. Under anaerobic conditions, little radioactivity from these compounds is incorporated i...

Neuronal degeneration that occurs in both ischemia and degenerative neurologic illnesses may involve excitotoxic mechanisms. In the present study, we examined whether cortical lesions with agonists acting at subtypes of glutamate receptors result in selective patterns of neuronal death. Injections of quinolinic acid, NMDA, homocysteic acid, kainic acid (KA), and alpha-amino-3-hydroxy-5-methylis...

BACKGROUND Autism spectrum disorders (ASDs) are relatively common neurodevelopmental conditions whose biological basis has been incompletely determined. Several biochemical markers have been associated with ASDs, but there is still no laboratory test for these conditions. METHODS We analyzed the metabolic profile of lymphoblastoid cell lines from 137 patients with neurodevelopmental disorders...

This mini-review provides a brief overview of the role of L-tryptophan in the synthesis of serotonin, quinolinic acid, and kynurenic acid, which are critically important for neuronal development and synaptogenesis, neuroimmune activity, and mitochondrial function. Tryptophan is not synthesised in the human body and it is only available in the diet. As an essential amino acid, it is required for...