scholarly journals Production of l-glutamate family amino acids in Corynebacterium glutamicum: Physiological mechanism, genetic modulation, and prospects

2021 ◽  
Vol 6 (4) ◽  
pp. 302-325
Author(s):  
Qi Sheng ◽  
Xiao-Yu Wu ◽  
Xinyi Xu ◽  
Xiaoming Tan ◽  
Zhimin Li ◽  
...  
Keyword(s):  
Amino Acids ◽  
Corynebacterium Glutamicum ◽  
Physiological Mechanism ◽  
Genetic Modulation

Coproduction of cell-bound and secreted value-added compounds: Simultaneous production of carotenoids and amino acids by Corynebacterium glutamicum

2018 ◽  
Vol 247 ◽  
pp. 744-752 ◽  
Author(s):  
Nadja A. Henke ◽  
Daniela Wiebe ◽  
Fernando Pérez-García ◽  
Petra Peters-Wendisch ◽  
Volker F. Wendisch
Keyword(s):  
Amino Acids ◽  
Corynebacterium Glutamicum ◽  
Value Added ◽  
Simultaneous Production

Endocrine and amino acid regulation of liver macroautophagy and proteolytic function

1994 ◽  
Vol 266 (1) ◽  
pp. G118-G122
Author(s):  
E. Bergamini ◽  
A. Del Roso ◽  
Z. Gori ◽  
P. Masiello ◽  
M. Masini ◽  
...  
Keyword(s):  
Amino Acids ◽  
Protein Degradation ◽  
Intraperitoneal Administration ◽  
Physiological Mechanism ◽  
Albino Rats ◽  
Sprague Dawley ◽  
Subsequent Increase ◽  
Stimulatory Agent ◽  
And Control

Regulation of liver macroautophagy and protein degradation by hormones and direct regulatory amino acids were studied in male 2-mo-old Sprague-Dawley albino rats with the use of the antilipolytic agent 3,5'-dimethylpyrazole (DMP; 12 mg/kg body wt ip) as a stimulatory agent. Injection of DMP decreased glutamine plasma levels and glutamine release from the perfused liver. Autophagic vacuoles were observed in the pericanalicular area of liver cells after 30 min. Levels and release of other regulatory amino acids did not exhibit any significant decrease but subsequently increased. Intraperitoneal administration of glutamine inhibited the proteolytic response. In conclusion, these studies demonstrate that in vivo induction and control of liver macroautophagy and protein degradation by the physiological mechanism (i.e., by shortage of nutrients) involve unbalanced and asynchronous changes in the levels of selected direct regulatory amino acids (i.e., a decrease in glutamine and a subsequent increase in leucine and tyrosine levels)

scholarly journals Anaerobic Growth of Corynebacterium glutamicum via Mixed-Acid Fermentation

2015 ◽  
Vol 81 (21) ◽  
pp. 7496-7508 ◽  
Author(s):  
Andrea Michel ◽  
Abigail Koch-Koerfges ◽  
Karin Krumbach ◽  
Melanie Brocker ◽  
Michael Bott
Keyword(s):  
Amino Acids ◽  
Corynebacterium Glutamicum ◽  
Tricarboxylic Acid Cycle ◽  
Model Organism ◽  
Anaerobic Growth ◽  
Efficient Production ◽  
Ph Homeostasis ◽  
Anaerobic Conditions ◽  
Acid Fermentation ◽  
Content Type

ABSTRACTCorynebacterium glutamicum, a model organism in microbial biotechnology, is known to metabolize glucose under oxygen-deprived conditions tol-lactate, succinate, and acetate without significant growth. This property is exploited for efficient production of lactate and succinate. Our detailed analysis revealed that marginal growth takes place under anaerobic conditions with glucose, fructose, sucrose, or ribose as a carbon and energy source but not with gluconate, pyruvate, lactate, propionate, or acetate. Supplementation of glucose minimal medium with tryptone strongly enhanced growth up to a final optical density at 600 nm (OD600) of 12, whereas tryptone alone did not allow growth. Amino acids with a high ATP demand for biosynthesis and amino acids of the glutamate family were particularly important for growth stimulation, indicating ATP limitation and a restricted carbon flux into the oxidative tricarboxylic acid cycle toward 2-oxoglutarate. Anaerobic cultivation in a bioreactor with constant nitrogen flushing disclosed that CO2is required to achieve maximal growth and that the pH tolerance is reduced compared to that under aerobic conditions, reflecting a decreased capability for pH homeostasis. Continued growth under anaerobic conditions indicated the absence of an oxygen-requiring reaction that is essential for biomass formation. The results provide an improved understanding of the physiology ofC. glutamicumunder anaerobic conditions.

scholarly journals Characterization of Methionine Export in Corynebacterium glutamicum

2005 ◽  
Vol 187 (11) ◽  
pp. 3786-3794 ◽  
Author(s):  
Christian Trötschel ◽  
Dietrich Deutenberg ◽  
Brigitte Bathe ◽  
Andreas Burkovski ◽  
Reinhard Krämer
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Corynebacterium Glutamicum ◽  
High Capacity ◽  
Futile Cycle ◽  
Two Component ◽  
Methionine Concentration ◽  
Metabolic Conditions ◽  
Export System

ABSTRACT Corynebacterium glutamicum is known for its effective excretion of amino acids under particular metabolic conditions. Concomitant activities of uptake and excretion systems would create an energy-wasting futile cycle; amino acid export systems are therefore tightly regulated. We have used a DNA microarray approach to identify genes for membrane proteins which are overexpressed under conditions of elevated cytoplasmic concentrations of methionine. One of these genes was brnF, coding for the larger subunit of BrnFE, a previously identified two-component isoleucine export system. By deletion, complementation, and overexpression of the brnFE genes in a C. glutamicum strain, in which the two uptake systems for methionine were inactivated, we identified BrnFE as being responsible for methionine export. In the presence of both substrates in the cytoplasm, BrnFE was found to transport isoleucine and methionine at similar rates. The expression of the brnFE gene cluster depends on an Lrp-type transcription factor and was shown to be strongly induced by increasing cytoplasmic methionine concentration. Methionine was a better inducer than isoleucine, indicating that methionine rather than isoleucine might be the native substrate of BrnFE. When the synthesis of BrnFE was blocked by chloramphenicol, fast methionine export was still observed, but only at greatly increased cytoplasmic levels of this amino acid. This indicates the presence of at least one other methionine export system, presumably with low affinity but high capacity. Under conditions where cytoplasmic methionine does not exceed a concentration of 50 mM, BrnFE is the dominant export system for this amino acid.

scholarly journals Feedback-Resistant Acetohydroxy Acid Synthase Increases Valine Production in Corynebacterium glutamicum

2005 ◽  
Vol 71 (1) ◽  
pp. 207-213 ◽  
Author(s):  
Veronika ElišÃ¯Â¿Â½kov� ◽  
Miroslav P�tek ◽  
Jiř� Hol�tko ◽  
Jan Nešvera ◽  
Damien Leyval ◽  
...  
Keyword(s):  
Amino Acids ◽  
Corynebacterium Glutamicum ◽  
Shuttle Vector ◽  
Branched Chain Amino Acids ◽  
Site Directed Mutagenesis ◽  
Enzyme Molecule ◽  
Acetohydroxy Acid Synthase ◽  
Wild Type ◽  
Allosteric Site ◽  
Branched Chain

ABSTRACT Acetohydroxy acid synthase (AHAS), which catalyzes the key reactions in the biosynthesis pathways of branched-chain amino acids (valine, isoleucine, and leucine), is regulated by the end products of these pathways. The whole Corynebacterium glutamicum ilvBNC operon, coding for acetohydroxy acid synthase (ilvBN) and aceto hydroxy acid isomeroreductase (ilvC), was cloned in the newly constructed Escherichia coli-C. glutamicum shuttle vector pECKA (5.4 kb, Kmr). By using site-directed mutagenesis, one to three amino acid alterations (mutations M8, M11, and M13) were introduced into the small (regulatory) AHAS subunit encoded by ilvN. The activity of AHAS and its inhibition by valine, isoleucine, and leucine were measured in strains carrying the ilvBNC operon with mutations on the plasmid or the ilvNM13 mutation within the chromosome. The enzyme containing the M13 mutation was feedback resistant to all three amino acids. Different combinations of branched-chain amino acids did not inhibit wild-type AHAS to a greater extent than was measured in the presence of 5 mM valine alone (about 57%). We infer from these results that there is a single binding (allosteric) site for all three amino acids in the enzyme molecule. The strains carrying the ilvNM13 mutation in the chromosome produced more valine than their wild-type counterparts. The plasmid-free C. glutamicum ΔilvA ΔpanB ilvNM13 strain formed 90 mM valine within 48 h of cultivation in minimal medium. The same strain harboring the plasmid pECKAilvBNC produced as much as 130 mM valine under the same conditions.

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