Intermediate Transport in Aromatic Amino Acid Synthesis of Higher Plants

Planta Medica ◽  
1990 ◽  
Vol 56 (06) ◽  
pp. 597-597
Author(s):  
G. Schultz ◽  
C. Leuschner ◽  
C. Schmidt ◽  
U. Homeyer
Keyword(s):  
Amino Acid ◽  
Aromatic Amino Acid ◽  
Higher Plants ◽  
Acid Synthesis ◽  
Amino Acid Synthesis

scholarly journals Staphylococcus aureus Transcriptome Data and Metabolic Modelling Investigate the Interplay of Ser/Thr Kinase PknB, Its Phosphatase Stp, the glmR/yvcK Regulon and the cdaA Operon for Metabolic Adaptation

2021 ◽  
Vol 9 (10) ◽  
pp. 2148
Author(s):  
Chunguang Liang ◽  
Ana Rios-Miguel ◽  
Marcel Jarick ◽  
Priya Neurgaonkar ◽  
Myriam Girard ◽  
...  
Keyword(s):  
Amino Acid ◽  
Aromatic Amino Acid ◽  
Acid Synthesis ◽  
Aureus Strain ◽  
Metabolic Adaptation ◽  
Wild Type ◽  
Amino Acid Synthesis ◽  
Metabolic Modelling ◽  
Pyrimidine Synthesis ◽  
Cell Functions

Serine/threonine kinase PknB and its corresponding phosphatase Stp are important regulators of many cell functions in the pathogen S. aureus. Genome-scale gene expression data of S. aureus strain NewHG (sigB+) elucidated their effect on physiological functions. Moreover, metabolic modelling from these data inferred metabolic adaptations. We compared wild-type to deletion strains lacking pknB, stp or both. Ser/Thr phosphorylation of target proteins by PknB switched amino acid catabolism off and gluconeogenesis on to provide the cell with sufficient components. We revealed a significant impact of PknB and Stp on peptidoglycan, nucleotide and aromatic amino acid synthesis, as well as catabolism involving aspartate transaminase. Moreover, pyrimidine synthesis was dramatically impaired by stp deletion but only slightly by functional loss of PknB. In double knockouts, higher activity concerned genes involved in peptidoglycan, purine and aromatic amino acid synthesis from glucose but lower activity of pyrimidine synthesis from glucose compared to the wild type. A second transcriptome dataset from S. aureus NCTC 8325 (sigB-) validated the predictions. For this metabolic adaptation, PknB was found to interact with CdaA and the yvcK/glmR regulon. The involved GlmR structure and the GlmS riboswitch were modelled. Furthermore, PknB phosphorylation lowered the expression of many virulence factors, and the study shed light on S. aureus infection processes.

scholarly journals Carbon flux through photosynthesis and central carbon metabolism show distinct patterns between algae, C3 and C4 plants

Nature Plants ◽  
2021 ◽  
Author(s):  
Haim Treves ◽  
Anika Küken ◽  
Stéphanie Arrivault ◽  
Hirofumi Ishihara ◽  
Ines Hoppe ◽  
...  
Keyword(s):  
Amino Acid ◽  
Higher Plants ◽  
Tricarboxylic Acid Cycle ◽  
Empirical Studies ◽  
Crop Improvement ◽  
Lipid Synthesis ◽  
Acid Synthesis ◽  
Central Carbon Metabolism ◽  
Amino Acid Synthesis

AbstractPhotosynthesis-related pathways are regarded as a promising avenue for crop improvement. Whilst empirical studies have shown that photosynthetic efficiency is higher in microalgae than in C3 or C4 crops, the underlying reasons remain unclear. Using a tailor-made microfluidics labelling system to supply 13CO2 at steady state, we investigated in vivo labelling kinetics in intermediates of the Calvin Benson cycle and sugar, starch, organic acid and amino acid synthesis pathways, and in protein and lipids, in Chlamydomonas reinhardtii, Chlorella sorokiniana and Chlorella ohadii, which is the fastest growing green alga on record. We estimated flux patterns in these algae and compared them with published and new data from C3 and C4 plants. Our analyses identify distinct flux patterns supporting faster growth in photosynthetic cells, with some of the algae exhibiting faster ribulose 1,5-bisphosphate regeneration and increased fluxes through the lower glycolysis and anaplerotic pathways towards the tricarboxylic acid cycle, amino acid synthesis and lipid synthesis than in higher plants.

Effects of Glyphosate on the Metabolism of Phenolic Compounds: VII. Root-Fed Amino Acids and Glyphosate Toxicity in Soybean (Glycine max) Seedlings

Weed Science ◽  
1981 ◽  
Vol 29 (3) ◽  
pp. 297-302 ◽  
Author(s):  
S. O. Duke ◽  
R. E. Hoagland
Keyword(s):  
Amino Acids ◽  
Glycine Max ◽  
Amino Acid ◽  
Phenolic Compounds ◽  
Aromatic Amino Acid ◽  
Aromatic Amino Acids ◽  
Acid Synthesis ◽  
Root Growth Inhibition ◽  
Shikimate Dehydrogenase ◽  
Amino Acid Synthesis

Several regimes of supplying exogenous aromatic amino acids to intact, 3-day-old, soybean [Glycine max(L.) Merr. ‘Hill’] seedlings by root uptake were tested to determine if growth retardation caused by root-fed, 0.5 mM glyphosate [N-(phosphonomethyl) glycine] could be reversed. Generally, root-fed levels of aromatic amino acids just below growth-retarding levels (e.g. 1 mM phenylalanine + 0.1 mM tyrosine) reversed root growth inhibition caused by glyphosate to a small (ca. 10%) but significant extent. Feeding aromatic amino acids for 1 to 3 days before glyphosate exposure did not enhance the reversal. Uptake and metabolism of root-fed, aromatic amino acids in control and glyphosate-treated plants were verified by increased levels of hydroxyphenolic compounds (end products of aromatic amino acid metabolism) and by uptake and incorporation of14C-labeled phenylalanine and tyrosine. On a fresh weight basis, glyphosate had no inhibitory effect on uptake or incorporation of these amino acids into protein or secondary phenolic compounds. After 3 days of exposure, glyphosate had no substantial effects on shikimate dehydrogenase activity in control or aromatic amino acid-fed seedlings. These data suggest that either root-fed aromatic amino acids are compartmentalized differently than the endogenous pools affected by glyphosate or that root-fed glyphosate exerts most of its effect on growth of soybean seedlings through means other than inhibition of aromatic amino acid synthesis.

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