In comparison to other pseudomonads, Pseudomonas aeruginosa grows poorly in L-lysine as a sole source of nutrient. In this study, the ldcA gene (lysine decarboxylase A; PA1818), previously identified as a member of the ArgR regulon of L-arginine metabolism, was found essential for L-lysine catabolism in this organism. LdcA was purified to homogeneity from a recombinant strain of Escherichia col...

The cell density-dependent acid sensitivity phenotypes of Escherichia coli strains K-12 and O157:H7 were examined with reference to three possible mechanisms of acid resistance. There was no evidence of any diffusible substance released from dead cells which could influence the cell density-dependent acid survival phenotype. Instead, cell density-dependent acid survival phenotype was associated...

Purified and partially purified ornithine decarboxylase (ODC) from rat heart was inhibited by basic polypeptides in vitro. Poly-L-arginine, the most effective, was inhibitory at a concentration as low as 0.1 microgram/ml; protamine and histone clearly inhibited ODC at concentrations higher than 2 micrograms/ml, but poly-L-lysine was less effective. The ability to inhibit ODC appeared to correla...

Heat-bleached oat (Avena sativa L. cv Porter) leaves lacking 70S chloroplast ribosomes have been used to demonstrate that four chloroplast-localized enzymes of pyrimidine nucleotide biosynthesis: aspartate carbamoyl-transferase, dihydroorotase, orotidine phosphoribosyl-transferase, and orotidine-5'-phosphate decarboxylase, are synthesized on cytoplasmic ribosomes. Two other chloroplast enzymes,...

A transcriptional regulator gene, designated adiY, was found downstream of the biodegradative arginine decarboxylase (adiA) gene (previously known as adi) of Escherichia coli. The arginine decarboxylase system is maximally induced under conditions of acidic pH, anaerobiosis and rich medium, and AdiY was found to increase the expression of adiA. The DNA sequence of adiY encodes a protein of 253 ...

Ornithine decarboxylase has been identified and characterized in the free-living nematode Caenorhabditis elegans. Unlike previously described ornithine decarboxylases, the enzyme activity is membrane-associated and remains in the membrane fraction after treatment with high salt, detergents or phosphatidylinositol-specific phospholipase C. Ornithine has an apparent Km value of 2.7 microM for orn...

A rapid medium for the detection of lysine and ornithine decarboxylase and arginine dihydrolase activity of 439 strains of gram-negative, nonfermenting bacteria was evaluated and compared with Moeller decarboxylase medium. Results were obtained in 4 to 24 h using the rapid medium, whereas Moeller medium often required extended (3 to 7 days) incubation. There was 100% agreement in the lysine tes...