The microflora of the chernozem soil mineralized 62% of the lactose retained on a column consisting of three 10-g layers of the soil at a daily flow of 48 mg of the sugar. Only 45% of the sugar was mineralized when the daily flow was 136 mg. The highest value of the beta-galactosidase activity in the system of heterocontinuous cultivation was two-fold with respect to batch cultivation. At a higher sugar concentration the enzyme activity in steady state was the same in the whole soil column. This value was reached first in the middle layer of the soil. At a lower concentration of the flowing sugar in steady state the highest enzyme activity was detected in the middle layer of the soil. In the upper layer the enzyme activity was one half, in the lower layer it began to decrease after reaching its maximum after 4 d of the incubation.

• MeSH
• Bacteria metabolism   MeSH
• beta-Galactosidase metabolism   MeSH
• Galactosidases metabolism   MeSH
• Fungi metabolism   MeSH
• Lactose metabolism   MeSH
• Soil Microbiology * MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• beta-Galactosidase MeSH
• Galactosidases MeSH
• Lactose MeSH

Intracellular concentration of cAMP regulates the synthesis of enzymes sensitive to catabolite repression. The relationship between the single and multiple induction of beta-galactosidase (EC 3.2.1.23), L-tryptophanase (EC 4.1.99.1), D-serine deaminase (EC 4.2.1.14), L-asparaginase (EC 3.5.1.1) and L-malate dehydrogenase (EC 1.1.1.37) was studied and the effect of cAMP level on the induction in Escherichia coli Crookes (ATCC 8739) was investigated. A varying degree of catabolite repression was observed during induction of individual enzymes induced separately on different energy sources. The synthesis of l-tryptophanase was most sensitive, whereas l-asparaginase was not influenced at all. Exogenous cAMP was found to overcome partially the catabolite repression of beta-galactosidase and D-serine deaminase, both during single induction. The synthesis of l-malate dehydrogenase was negatively influenced by the multiple induction even in the presence of cAMP; on the other hand, the synthesis of l-tryptophanase was stimulated, independently of the level of the exogenous cAMP. Similarly, the activity of L-asparaginase slightly but significantly increased during the multiple induction of all five enzymes; here too the activity increase did not depend on exogenous cAMP.

• MeSH
• Cyclic AMP pharmacology   MeSH
• Asparaginase biosynthesis   MeSH
• beta-Galactosidase biosynthesis   MeSH
• Enzyme Induction drug effects   MeSH
• Enzyme Repression * drug effects   MeSH
• Escherichia coli enzymology   MeSH
• Indoleamine-Pyrrole 2,3,-Dioxygenase MeSH
• L-Serine Dehydratase biosynthesis   MeSH
• Malate Dehydrogenase biosynthesis   MeSH
• Tryptophanase biosynthesis   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Cyclic AMP MeSH
• Asparaginase MeSH
• beta-Galactosidase MeSH
• Indoleamine-Pyrrole 2,3,-Dioxygenase MeSH
• L-Serine Dehydratase MeSH
• Malate Dehydrogenase MeSH
• Tryptophanase MeSH

When inducing simultaneously beta-galactosidase and tryptophanase in a batch culture either the synthesis of tryptophanase or of both enzymes is decreased due to an insufficient cAMP concentration. The addition of this nucleotide can overcome this decrease. In a continuous culture both enzymes are synthesized at the maximum rate, as the amount of cAMP produced during carbon limitation of growth is probably sufficient for the simultaneous synthesis of both enzymes. In the beta-galactosidase hyperproduction mutant cultivated continuously the level of beta-galactosidase markedly decreases when tryptophanase is simultaneously induced. Also this decrease is caused by cAMP insufficiency and can be overcome by increasing its concentration. cAMP is thus an important regulatory factor of both enzymes and becomes a limiting factor in their simultaneous synthesis; a competition for this regulatory compound apparently occurs and probably also a different mutual affinity of the regulatory complex with the promoter site of the enzyme operons is involved.

• MeSH
• Cyclic AMP pharmacology   MeSH
• beta-Galactosidase biosynthesis   MeSH
• Enzyme Induction drug effects   MeSH
• Escherichia coli drug effects   enzymology   MeSH
• Galactosidases biosynthesis   MeSH
• Kinetics MeSH
• Lyases biosynthesis   MeSH
• Tryptophanase biosynthesis   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Cyclic AMP MeSH
• beta-Galactosidase MeSH
• Galactosidases MeSH
• Lyases MeSH
• Tryptophanase MeSH

During a simultaneous induction of three enzymes which are subject to catabolite repression (beta-galactosidase, tryptophanase and amylomaltase, or beta-galactosidase, tryptophanase and D-serine deaminase) in a batch culture, the rates of synthesis of beta-galactosidase and tryptophanase decreases, while the rates of synthesis of amylomaltase and D-serine deaminase remain unaffected. The addition of cAMP brings about a considerable increase of the rate of synthesis of D-serine deaminase and a partial synthesis rate increase of beta-galactosidase whihle the synthesis rate of tryptophanase remains lowered and the synthesis rate of amylomaltase remains unaffected. In a continuous culture beta-galactosidase, tryptophanase and D-serine deaminase are synthesized simultaneously at a maximum rate without mutual influence. The addition of cAMP increases the rate of synthesis of all three enzymes.

• MeSH
• Cyclic AMP pharmacology   MeSH
• beta-Galactosidase biosynthesis   MeSH
• Enzyme Induction MeSH
• Glycogen Debranching Enzyme System * MeSH
• Escherichia coli enzymology   MeSH
• Galactosidases biosynthesis   MeSH
• Glucans biosynthesis   MeSH
• Glucosyltransferases biosynthesis   MeSH
• Kinetics MeSH
• L-Serine Dehydratase biosynthesis   MeSH
• Lyases biosynthesis   MeSH
• Tryptophanase biosynthesis   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• 4 alpha-glucanotransferase MeSH Browser
• Cyclic AMP MeSH
• beta-Galactosidase MeSH
• Glycogen Debranching Enzyme System * MeSH
• Galactosidases MeSH
• Glucans MeSH
• Glucosyltransferases MeSH
• L-Serine Dehydratase MeSH
• Lyases MeSH
• Tryptophanase MeSH