Showing papers by "Arnold L. Demain published in 1969"
TL;DR: Experiments are described which indicate that Pseudomonas denitrificans, an organism that overproduces vitamin B(12), uses the B( 12) pathway exclusively for methionine synthesis.
Abstract: Experiments are described which indicate that Pseudomonas denitrificans, an organism that overproduces vitamin B(12), uses the B(12) pathway exclusively for methionine synthesis.
22 citations
TL;DR: A generally applicable method for detecting colonies deficient in glucose-6-phosphate dehydrogenase was developed and mutants obtained were found to be auxotrophic for tryptophan, but neither the mutants nor the revertants could grow as rapidly as the parent culture in glucose, in gluconate, or in a complex medium.
Abstract: Corynebacterium glutamicum is a member of a group of taxonomically related glutamate-excreting bacteria which utilize glucose both by the Embden-Meyerhof and the pentose phosphate pathways, the latter sequence accounting for 10 to 38% of the glucose metabolized. Some of the properties of glucose-6-phosphate dehydrogenase in crude extracts of C. glutamicum were studied. The enzyme was rapidly inactivated by dilution in tris (hydroxymethyl)aminomethane-hydrochloride buffer. This inactivation was prevented by the presence of 0.45 m NaCl. Mg++ was required for enzyme activity, but Mn++, Ca++, Sr++, and Ba++ were equally effective. Growth of the organism under differing conditions did not markedly affect the specific activity of the enzyme. A generally applicable method for detecting colonies deficient in glucose-6-phosphate dehydrogenase was developed. Mutants so obtained were found to be auxotrophic for tryptophan. Upon reversion of the tryptophan requirement, the revertants still retained the property of glucose-6-phosphate dehydrogenase deficiency. Neither the mutants nor the revertants could grow as rapidly as the parent culture in glucose, in gluconate, or in a complex medium.
17 citations
TL;DR: In line with the induction hypothesis, chloramphenicol inhibited the metabolism of citrate by glucose-grown resting cells but had no such effect on the citrate-adapted cells.
Abstract: Triggering of glutamate excretion by penicillin is thought to occur by increasing cell permeability. It seemed odd that glucose-grown resting cells, after penicillin treatment, would not convert citrate to extracellular glutamate especially since citrate had been reported to be a substrate for the glutamate fermentation. Citrate was not even taken up by such cells. Upon addition of at least 2 percent glucose, citrate was converted to extracellular glutamate. Both glucose and citrate were used simultaneously and citrate metabolism continued even after sugar was exhausted. It was suspected that glucose was required as energy source for induction of a citrate-transport system. Resting cells pregrown in glucose plus citrate, were indeed found to take up citrate and convert it to extracellular glutamate even in the absence of sugar. In line with the induction hypothesis, chloramphenicol inhibited the metabolism of citrate by glucose-grown resting cells but had no such effect on the citrate-adapted cells. The a...
10 citations
TL;DR: Citrate reversal of iodoacetate inhibition of glutamate synthesis is nonmetabolic, while reversal of fluoride inhibition is metabolic, occurring only at low Mg concentrations.
Abstract: Citrate reversal of iodoacetate inhibition of glutamate synthesis is nonmetabolic. Reversal of fluoride inhibition is metabolic, occurring only at low Mg concentrations.
6 citations
Patent•
23 Jan 1969TL;DR: In this paper, a Cis-1,2-epoxypropyl (COPP) phosphonic acid is produced in enhanced yields by growing suitable species of Streptomyces in fermentation mediums containing a mercapto-containing compound.
Abstract: (-) (Cis-1,2-epoxypropyl) phosphonic acid is produced in enhanced yields by growing suitable species of Streptomyces in fermentation mediums containing a mercapto-containing compound. The phosphonic acid and derivatives thereof, such as salts, are antibacterial substances which are active against both grampositive and gram-negative bacteria.