Aerobic biodegradation of 3-aminobenzoate by Gram-negative bacteria involves intermediate formation of 5-aminosalicylate as ring-cleavage substrate

Abstract The aerobic metabolism of 3-aminobenzoate by bacteria was studied. Bacterial strains degrading 3-aminobenzoate were obtained by enrichment with 3-aminobenzoate (strain Ia3) or 5-aminosalicylate (strains BN9 and 5AS1). During growth with 3-aminobenzoate, strain Ia3 and strain 5AS1 transiently accumulated 5-aminosalicylate in the culture broth. In the presence of inhibitors of 5-aminosalicylate 1,2-dioxygenase, resting cells of all three strains converted 3-aminobenzoate to stoichiometric amounts of 5-aminosalicylate. 5-Aminosalicylate 1,2-dioxygenase activity was induced in all strains after growth with 3-aminobenzoate or 5-aminosalicylate, but not after growth in complex media.     

<Emphasis Type="Italic">Pycnoscelus surinamensis</Emphasis> (Linnaeus, 1758) (Blaberoidea: Blaberidae), a cockroach with a possible association with the ant <Emphasis Type="Italic">Brachymyrmex cordemoyi</Emphasis> Forel, 1895 (Hymenoptera: Formicidae) and which may be exhibiting a domiciliation trend.

In the present paper, we report on the occurrence of the cockroach Pycnoscelus surinamensis (Linnaeus, 1758) in Brachymyrmex cordemoyi Forel, 1895 nests, indicating a possible symbiosis between these two species. Also, the finding of intradomicile P. surinamensis nymphs may indicate this species is extending its habitat to human habitations, i.e. changing its ecological category from peridomestic to domestic.     

Improved retention of heme with increased resolution of microsomal proteins in polyacrylamide gel electrophoresis

Polyacrylamide gel electrophoresis, using lithium dodecyl sulfate instead of the sodium salt, was used to analyze rat hepatic microsomal hemoproteins. Good resolution of hepatic microsomal proteins was obtained with retention of approximately half of the total microsomal heme on the proteins with molecular weights of 45,000 to 50,000. Both the protein resolution and heme retention are better than with electrophoresis procedures previously described. Treatment of rats with chemicals that either increase or decrease microsomal cytochrome P-450 produced proportional changes in the heme associated with the proteins of 45,000 to 50,000 molecular weights on the gel.     

Structure and function of mononuclear molybdenum enzymes

 An account of recent advances in our understanding of enzymes possessing mononuclear molybdenum active sites is presented. On the basis of a variety of structural studies, and in conjunction with comparisons among the growing number of these enzymes for which the amino acid sequences are known, it is evident that these enzymes fall into three principal families as represented by xanthine oxidase, sulfite oxidase and DMSO reductase. Structural features of the active sites of these three families are compared and contrasted, and specific mechanistic implications of the recently reported crystal structure for the aldehyde oxidoreductase from Desulfovibrio gigas are discussed. Received: 9 April 1996 / Accepted: 14 June 1996