scholarly journals The Impact of Streptozotocin-induced Diabetes Mellitus on Cyclic Nucleotide Regulation of Skeletal Muscle Amino Acid Metabolism in the Rat

1980 ◽  
Vol 65 (2) ◽  
pp. 478-487 ◽  
Author(s):  
Alan J. Garber
Keyword(s):  
Diabetes Mellitus ◽  
Skeletal Muscle ◽  
Amino Acid ◽  
Cyclic Nucleotide ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Nucleotide Regulation ◽  
Streptozotocin Induced Diabetes ◽  
The Impact

scholarly journals Impact of Classical Strain Improvement of Penicillium rubens on Amino Acid Metabolism during β-Lactam Production

2019 ◽  
Vol 86 (3) ◽  
Author(s):  
Min Wu ◽  
Ciprian G. Crismaru ◽  
Oleksandr Salo ◽  
Roel A. L. Bovenberg ◽  
Arnold J. M. Driessen
Keyword(s):  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Strain Improvement ◽  
Tryptophan Synthase ◽  
Cysteine Biosynthesis ◽  
Penicillin Production ◽  
Content Type ◽  
Classical Strain ◽  
The Impact

ABSTRACT To produce high levels of β-lactams, the filamentous fungus Penicillium rubens (previously named Penicillium chrysogenum) has been subjected to an extensive classical strain improvement (CSI) program during the last few decades. This has led to the accumulation of many mutations that were spread over the genome. Detailed analysis reveals that several mutations targeted genes that encode enzymes involved in amino acid metabolism, in particular biosynthesis of l-cysteine, one of the amino acids used for β-lactam production. To examine the impact of the mutations on enzyme function, the respective genes with and without the mutations were cloned and expressed in Escherichia coli, purified, and enzymatically analyzed. Mutations severely impaired the activities of a threonine and serine deaminase, and this inactivates metabolic pathways that compete for l-cysteine biosynthesis. Tryptophan synthase, which converts l-serine into l-tryptophan, was inactivated by a mutation, whereas a mutation in 5-aminolevulinate synthase, which utilizes glycine, was without an effect. Importantly, CSI caused increased expression levels of a set of genes directly involved in cysteine biosynthesis. These results suggest that CSI has resulted in improved cysteine biosynthesis by the inactivation of the enzymatic conversions that directly compete for resources with the cysteine biosynthetic pathway, consistent with the notion that cysteine is a key component during penicillin production. IMPORTANCE Penicillium rubens is an important industrial producer of β-lactam antibiotics. High levels of penicillin production were enforced through extensive mutagenesis during a classical strain improvement (CSI) program over 70 years. Several mutations targeted amino acid metabolism and resulted in enhanced l-cysteine biosynthesis. This work provides a molecular explanation for the interrelation between secondary metabolite production and amino acid metabolism and how classical strain improvement has resulted in improved production strains.

Glucose and amino acid metabolism in an established line of skeletal muscle cells

1978 ◽  
Vol 96 (3) ◽  
pp. 309-317 ◽  
Author(s):  
William M. Pardridge ◽  
Mayer B. Davidson ◽  
Delia Casanello-Ertl
Keyword(s):  
Skeletal Muscle ◽  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Established Line
Sign in / Sign up

Export Citation Format

Share Document