1-Methoxypyrene and 1,6-dimethoxypyrene: two novel metabolites in fungal metabolism of polycyclic aromatic hydrocarbons

The metabolism of pyrene by Penicillium glabrum strain TW 9424, a strain isolated from a site contaminated with polycyclic aromatic hydrocarbons (PAHs) was investigated in submerged cultures. The metabolites formed were identified as 1-hydroxypyrene, 1,6- and 1,8-dihydroxypyrene, 1,6- and 1,8-pyrenequinone, and 1-pyrenyl sulfate. In addition, two new metabolites were isolated and identified by UV, ¹H nuclear magnetic resonance, and mass spectroscopy as 1-methoxypyrene and 1,6-dimethoxypyrene. Experiments with [methyl-³H]S-adenosyl-l-methionine (SAM) revealed that SAM is the coenzyme that provides the methyl group for the methyltransferase involved. To our knowledge, this is the first time that methoxylated metabolites of PAHs have been isolated from fungal cultures. Received: 27 August 1996 / Accepted: 8 January 1997     

Regional Distribution of Methionine Adenosyltransferase in Rat Brain as Measured by a Rapid Radiochemical Method

Abstract: The distribution of methionine adenosyltransferase (MAT) in the CNS of the rat was studied by use of a rapid, sensitive and specific radiochemical method. The S -adenosyl-[methyl-¹⁴C] l -methionine ([¹⁴C]SAM) generated by adenosyl transfer from ATP to [methyl-¹⁴C] l -methionine is quantitated by use of a SAM-consuming transmethylation reaction. Catechol O -methyltransferase (COMT), prepared from rat liver, transfers the methyl-¹⁴C group of SAM to 3,4-dihydroxybenzoic acid. The ¹⁴C-labelled methylation products, vanillic acid and isovanillic acid, are separated from unreacted methionine by solvent extraction and quantitated by liquid scintillation counting. Compared to other methods of MAT determination, which include separation of generated SAM from methionine by ion-exchange chromatography, the assay described exhibited the same high degree of specificity and sensitivity but proved to be less time consuming. MAT activity was found to be uniformly distributed between various brain regions and the pituitary gland of adult male rats. In the pineal gland the enzyme activity is about tenfold higher.     

Unexpected relationships between bacteriophage lambda hypothetical proteins and bacteriophage T4 tail-fiber proteins

Hypothetical lambda protein ORF314 shows significant homology with the carboxyl end of phage T4 tail-fiber protein gp37. Homology can also be demonstrated between hypothetical lambda protein ORF194 and a fragment of bacteriophage T4 protein gp38. This sequence homology is also reflected in the genomic sequences of these two phages.