PubMed Health⌕ Search

Biomedical subjects

D Schlee

Publications and source records attributed to D Schlee.

At least 19 recordsLinked to original sources
PubMed1978

[Differences in proline metabolism of a peptide alkaloid producing and a nonproducing strain of Claviceps purpurea].

Two strains (pepty 695 and pur 221) of Claviceps purpurea have been used to study the dependence of proline turnover on incubation time (1, 3, 6, and 12 hours) under different culture conditions (synthetic saccharose-citrate medium NL 720 and complex wort medium M 107) by means of tracer technique. In the saprophytically ergotoxine producing strain pepty 695 the proline is utilized in the protein and alkaloid biosyntheses. On the other hand, under non-producing conditions (M 10) the radioactivity of proline-14C is incorporated into many fractions and finally into CO2. In submerged culture (NL 720) the Claviceps strain pur 221 which does not produce ergolines uses proline only to a small extent in the protein biosynthesis, while most of this amino acid is not metabolized. The extent of uptake of proline is not correlated with the alkaloid synthesis. For comparison the turnover of L-glutamate-14C and D,L-ornithine-1-14C by strain pepty 695 cultivated in the NL 720 medium has been studied.

Claviceps↗
PubMed1976

Regulation of 6-hydroxy-2,4,5-triaminopyrimidine synthesis by riboflavin and iron in riboflavin-deficient mutants of Pichia guilliermondii yeast.

The effect of riboflavin and iron on 6-hydroxy-2,4,5-triaminopyrimidine synthesis rate was investigated in the cultures of the yeast Pichia guilliermondii (rib2 mutants) with the blocked second reaction to flavinogenesis. It was shown that riboflavin inhibited the 6-hydroxy-2,4,5-triaminopyrimidine synthesis rate in iron-rich and iron-deficient cells of mutants with low riboflavin requirements. Cycloheximide did not prevent the stimulation of 6-hydroxy-2,4,5-triaminopyrimidine synthesis caused by riboflavin starvation. 7-methyl-8-trifluoromethyl-10-(1'-D-ribityl)isoalloxazine strongly inhibited the 6-hydroxy-2,4,5-triaminopyrimidine synthesis, while 7-methyl-8-trifluoro-methyl-10-(beta-hydroxyethyl)izoalloxazine and galactoflavin exerted only a slight effect on this process. The 6-hydroxy-2,4,5-triaminopyrimidine synthesis rate in iron-deficient cells was significantly higher than in iron-rich cells. The 2,2'-dipyridyl treatment of iron-rich cells caused the stimulation of 6-hydroxy-2,4,5-triaminopyrimidine synthesis and cycloheximide abolished this effect. The results suggest that the activity of the first enzyme of flavinogenesis (guanylic cyclohydrolase) is under the control of feedback inhibition by flavins and the biosynthesis of this enzyme is regulated by iron.

2,2'-Dipyridyl↗