In 1953, Monod and Cohen-Bazire as well as Cohn, Cohen, and Monod showed that an amino acid may repress the last enzyme in the biochemical pathway which leads to the formation of that amino acid. Four years later, H. J. Vogel found that arginine, when added to a growing bacterial culture, represses the formation of acetyl ornithinase (one of the early enzymes along the biochemical pathway leadi...

The elective isolation of a soil microorganism, tentatively assigned to the genus Arthrobacter, which produced an extracellular neuraminidase is described. The secretion of neuraminidase from washed cells in minimal medium required the presence of sialo-containing glycoproteins, whereas free N-acetyl-neuraminic asid of N-acetylmannosamine were poor inducers. No enzyme could be dected in the ind...

considering great medicinal value of hyssopus officinalis l. and possibility of its mass production through in vitro culture, two individual experiments was conducted. effect of various concentrations (0, 2.2, 4.4 and 11 µmol) of tdz and bap in combination with 1 µmol of iaa on direct regeneration from nodal explants were assessed. significant difference between treatments was observed (p≤ 0.01...

Retinoic acid, retinol, metinylacetate, and retinal induced activities of lysosomal enzymes, such as lysozyme, acid pro tease, and acid phosphatase, in mouse myeloid leukemia cells (Ml ), while the pynidyl analog of metinoicacid had no effect. Retinoic acid was the most potent inducer of lysosomal enzyme activities. The induction of lysozyme activity by retinoic acid was inhibited by treatment ...

Synthesis of wild-type Neurospora crassa assimilatory nitrate reductase is induced in the presence of nitrate ions and repressed in the presence of ammonium ions. Effects of several Neurospora mutations on the regulation of this enzyme are shown: (i) the mutants, nit-1 and nit-3, involving separate lesions, lack reduced nicotinamide adenine dinucleotide (NADPH)-nitrate reductase activity and at...

In a previous work, we demonstrated that the induction of arginase I favored the replication of Leishmania inside macrophages. Now we have analyzed the differential expression of this enzyme in the mouse model of L. major infection. Ours results show that arginase I is induced in both susceptible and resistant mice during the development of the disease. However, in BALB/c-infected tissues, the ...

Epinephrine, norepinephrine, and isoproterenol prevent the induction of rat liver glucokinase (EC 2.7.1.2) produced by the administration of glucose to animals with low levels of the enzyme. The low levels of glucokinase were obtained by feeding the animals a carbohydrate-free diet for 6 days. When epinepbrine was given 4 hours after the administration of carbohydrate there was only a slight in...

Retinoic acid, retinol, retinyl acetate, and retinal induced activities of lysosomal enzymes, such as lysozyme, acid protease, and acid phosphatase, in mouse myeloid leukemia cells (M1), while the pyridyl analog of retinoic acid had no effect. Retinoic acid was the most potent inducer of lysosomal enzyme activities. The induction of lysozyme activity by retinoic acid was inhibited by treatment ...