γ-Glutamylglutamine and Taurine Concentrations Are Decreased in the Cerebrospinal Fluid of Drug-Naive Patients with Schizophrenic Disorders

Abstract: HPLC and gas chromatography-mass spectrometry analyses of 18 amino acids, N -acetylaspartate, N -acetylaspartyglutamate, and 5-hydroxyindoleacetic acid, derived from serotonin, and homovanillic acid, derived from dopamine, were performed in CSF collected from a group of patients with schizophrenia who either had been drug free for at least 1 year (n = 5) or were drug naive for psychotropic drugs (n = 21) and in 15 control subjects. Significant differences were found only for taurine (15% lower in the patients) and isoleucine (7% higher). A number of unidentified substances were detected, one of which proved to be markedly reduced (16%) among the schizophrenic patients. Liquid chromatography-mass spectrometry with continuous flow-fast atom bombardment interface allowed us to identify this substance as γ-glutamyglutamine. The decreased level of γ-glutamylglutamine may reflect a deficiency in the γ-glutamyltransferase system, a system probably involved in glutamate uptake, or a deficiency in glutamine, an important precursor of releasable glutamate. Although glutamate was nonsignificantly reduced in the patients, it was one of the five substances (including γ-glutamylglutamine) that were necessary for the best discrimination between the schizophrenic patients and the controls. These findings support the notion that the glutamatergic system is affected in schizophrenic disorders. In addition, they underscore the need to apply rigid bioanalytical techniques and use drug-naive patients to gain in-depth information on the pathophysiology of brain disorders such as schizophrenia.     

Determination of the molecular weight of Saccharomyces cerevisiae nuclear DNA

Viscoelastic retardation-time experiments on the DNA released from spheroplasts of the yeast Saccharomyces cerevisiae yield a molecular weight of 2 × 10⁹ for the largest DNA, assuming linear unbranched DNA, and of 4.3 × 10⁹ assuming circular unbranched DNA. Both log and stationary-phase cells give the same results. Comparison of these results with the nuclear DNA content of S. cerevisiae determined by renaturation kinetics suggests that the largest piece of DNA in the yeast nucleus may, at least during part of the cell cycle, consist of from one-fourth to all of the yeast genome.