Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Construction of l-Lysine-, l-Threonine-, or l-Isoleucine-Overproducing Strains of Corynebacterium glutamicum (1996)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 782 (1996), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1996.tb40544.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Molecular analysis of the Corynebacterium glutamicum gdh gene encoding glutamate dehydrogenase (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Molecular microbiology 6 (1992), S. 0 
    Details
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The Corynebacterium glutamicum gdh gene encoding NADP-dependent glutamate dehydrogenase (GDH) has been isolated by complementation of the Escherichia coli gdh mutant PA340. The gdh gene was subcloned into the E. coli/C. glutamicum shuttle vector pEK0 and introduced into C. glutamicum. Recombinant strains showed approximately eightfold higher specific GDH activity (15U mg protein-1) relative to the wild type (1.8U mg protein -1). Physiological studies with wild-type and recombinant C. glutamicum strains revealed no indication of significant regulation of gdh expression. The DNA sequence of 2082 bp, including the gdh gene, 5′-, and 3′-flanking regions, was determined. The structural gene consists of 1344 bp and codes for a polypeptide of 448 amino acid residues (Mr 49152) showing up to 53.6% identity with reported amino acid sequences of glutamate dehydrogenases from other organisms. Northern blot hybridization revealed a 1.65 kb mRNA transcript, indicating that the gdh gene of C. glutamicum is monocistronic. Transcription occurred from a G residue located 284bp upstream of the AUG considered to be the translational initiation codon.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2958.1992.tb01474.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Construction of l-Isoleucine Overproducing Strains of Corynebacterium glutamicum (1999)
    Springer
    Naturwissenschaften 86 (1999), S. 33-38 
    Details
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Notes: Corynebacterium glutamicum is used for the industrial production of the amino acids l-glutamate (1×106 tons/year) and l-lysine (300×103 tons/year). The classical approach to obtain amino acid overproducing strains of C. glutamicum was mutagenesis and then a selection of mutants. In the past 10 years the genetic engineering and amplification of genes have become fascinating methods for studying metabolic pathways in greater detail and for constructing microbial strains with desired genotypes. To obtain l-isoleucine overproducing strains of C. glutamicum we therefore studied the l-isoleucine biosynthesis by overexpression of the various corresponding genes. To enable a flux increase in recombinant strains all genes specific for l-threonine and l-isoleucine biosynthesis were cloned from this bacterium. We demonstratet that amplification of the feedback inhibition insensitive homoserine dehydrogenase and homoserine kinase in a high l-lysine overproducing strain enable the channeling of the carbon flow from the intermediate l-aspartate semialdehyde towards homoserine, resulting in an accumulation of l-threonine. To obtain effective l-isoleucine overproduction a deregulated threonine dehydratase was overexpressed in l-threonine producing strains of C. glutamicum. In this way the l-threonine was converted to l-isoleucine, which was secreted up to 30 g/l into the culture medium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001140050565
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    13C NMR studies of the fluxes in the central metabolism of Corynebacterium glutamicum during growth and overproduction of amino acids in batch cultures (1995)
    Springer
    Applied microbiology and biotechnology 44 (1995), S. 489-495 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  The carbon flux distribution in the central metabolism of Corynebacterium glutamicum was studied in batch cultures using [1-13C]- and [6-13C]glucose as substrate during exponential growth as well as during overproduction of L-lysine and L-glutamate. Using the 13C NMR data in conjunction with stoichiometric metabolite balances, molar fluxes were quantified and normalised to the glucose uptake rate, which was set to 100. The normalised molar flux via the hexose monophosphate pathway was 40 during exponential growth, whereas it was only 17 during L-glutamate production. During L-lysine production, the normalised hexose monophosphate pathway flux was elevated to 47. Thus, the carbon flux via this pathway correlated with the NADPH demand for bacterial growth and L-lysine overproduction. The normalised molar flux in the tricarboxylic acid cycle at the level of 2-oxoglutarate dehydrogenase was 100 during exponential growth and 103 during L-lysine secretion. During L-glutamate formation, the normalised flux through the tricarboxylic acid cycle was reduced to 60. In contrast to earlier NMR studies with C. glutamicum, no significant activity of the glyoxylate pathway could be detected. All experiments indicated a strong in vivo flux from oxaloacetate back to phosphoenolpyruvate and/or pyruvate, which might be due to phosphoenolpyruvate carboxykinase activity in C. glutamicum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002530050587
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    13C NMR studies of the fluxes in the central metabolism of Corynebacterium glutamicum during growth and overproduction of amino acids in batch cultures (1995)
    Springer
    Applied microbiology and biotechnology 44 (1995), S. 489-495 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The carbon flux distribution in the central metabolism of Corynebacterium glutamicum was studied in batch cultures using [1-13C]- and [6-13C]glucose as substrate during exponential growth as well as during overproduction of l-lysine and l-glutamate. Using the 13C NMR data in conjunction with stoichiometric metabolite balances, molar fluxes were quantified and normalised to the glucose uptake rate, which was set to 100. The normalised molar flux via the hexose monophosphate pathway was 40 during exponential growth, whereas it was only 17 during l-glutamate production. During l-lysine production, the normalised hexose monophosphate pathway flux was elevated to 47. Thus, the carbon flux via this pathway correlated with the NADPH demand for bacterial growth and l-lysine overproduction. The normalised molar flux in the tricarboxylic acid cycle at the level of 2-oxoglutarate dehydrogenase was 100 during exponential growth and 103 during l-lysine secretion. During l-glutamate formation, the normalised flux through the tricarboxylic acid cycle was reduced to 60. In contrast to earlier NMR studies with C. glutamicum, no significant activity of the glyoxylate pathway could be detected. All experiments indicated a strong in vivo flux from oxaloacetate back to phosphoenolpyruvate and/or pyruvate, which might be due to phosphoenolpyruvate carboxykinase activity in C. glutamicum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00169949
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Propionate assimilation by methanogenic bacteria (1983)
    Springer
    Archives of microbiology 136 (1983), S. 106-110 
    Details
    ISSN: 1432-072X
    Keywords: Propionate assimilation ; Isoleucine biosynthesis ; Methanogenic bacteria ; Methanobacterium thermoautotrophicum ; Methanobrevibacter arboriphilus ; Methanosarcina barkeri ; 2-Methylbutyrate assimilation ; Regulation of isoleucine biosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Methanobacterium thermoautotrophicum, Methanobrevibacter arboriphilus, and Methanosarcina barkeri were found to assimilate propionate when growing on media supplemented with this volatile fatty acid. [1-14C]propionate was almost exclusively incorporated into isoleucine, only C-2 of which became labelled. Assimilation of propionate by M. thermoautotrophicum was specifically inhibited by isoleucine, by 2-methylbutyrate, and by 2-oxobutyrate, whereas there was little or no effect by leucine, valine, butyrate, and acetate. This finding indicates that propionate assimilation is under regulatory control by intermediates and/or the product of isoleucine biosynthesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00404782
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Unusual pathway of isoleucine biosynthesis in Methanobacterium thermoautotrophicum (1983)
    Springer
    Archives of microbiology 136 (1983), S. 111-113 
    Details
    ISSN: 1432-072X
    Keywords: Isoleucine biosynthesis ; Citramalate ; Methanogenic bacteria ; Methanobacterium thermoautotrophicum ; Threonine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Methanobacterium thermoautotrophicum was grown on H2 and CO2 in a medium supplemented with [U-14C]threonine. Surprisingly, only threonine and not isoleucine in the cell protein became labelled indicating that the usual pathway of isoleucine biosynthesis via threonine is not operative in this anaerobic archaebacterium. Labelling studies with [1-14C]pyruvate, [2-14C]pyruvate and [1,4-14C]-succinate succinate revealed that isoleucine is probably synthesized from pyruvate and acetyl-CoA via citramalate as an intermediate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00404783
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    C3-Carboxylation as an anaplerotic reaction in phosphoenolpyruvate carboxylase-deficient Corynebacterium glutamicum (1996)
    Springer
    Archives of microbiology 165 (1996), S. 387-396 
    Details
    ISSN: 1432-072X
    Keywords: Key words Corynebacterium glutamicum ; Anaplerotic ; reactions ; Phosphoenolpyruvate carboxylase ; Isocitrate ; lyase ; Glyoxylate cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phosphoenolpyruvate carboxylase (PEPCx) has recently been found to be dispensable as an anaplerotic enzyme for growth and lysine production of Corynebacterium glutamicum. To clarify the role of the glyoxylate cycle as a possible alternative anaplerotic sequence, defined PEPCx- and isocitrate-lyase (ICL)-negative double mutants of C. glutamicum wild-type and of the l-lysine-producing strain MH20-22B were constructed by disruption of the respective genes. Analysis of these mutants revealed that the growth on glucose and the lysine productivity were identical to that of the parental strains. These results show that PEPCx and the glyoxylate cycle are not essential for growth of C. glutamicum on glucose and for lysine production and prove the presence of another anaplerotic reaction in this organism. To study the anaplerotic pathways in C. glutamicum further, H13CO3 –-labeling experiments were performed with cells of the wild-type and a PEPCx-negative strain growing on glucose. Proton nuclear magnetic resonance analysis of threonine isolated from cell protein of both strains revealed the same labeling pattern: about 37% 13C enrichment in C-4 and 3.5% 13C enrichment in C-1. Since the carbon backbone of threonine corresponds to that of oxaloacetate, the label in C-4 of threonine positively identifies the anaplerotic pathway as a C3-carboxylation reaction that also takes place in the absence of PEPCx.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002030050342
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Regulation of acetate metabolism in Corynebacterium glutamicum: transcriptional control of the isocitrate lyase and malate synthase genes (1997)
    Springer
    Archives of microbiology 168 (1997), S. 262-269 
    Details
    ISSN: 1432-072X
    Keywords: Key wordsCorynebacterium glutamicum ; Acetate ; metabolism ; Acetate kinase ; Phosphotransacetylase ; Isocitrate lyase ; Malate synthase ; Acetyl-CoA ; Acetyl-phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the amino-acid-producing microorganism Corynebacterium glutamicum, the specific activities of the acetate-activating enzymes acetate kinase and phosphotransacetylase and those of the glyoxylate cycle enzymes isocitrate lyase and malate synthase were found to be high when the cells were grown on acetate (0.8, 2.9, 2.1, and 1.8 U/mg protein, respectively). When the cells were grown on glucose or on other carbon sources such as lactate, succinate, or glutamate, the specific activities were two- to fourfold (acetate kinase and phosphotransacetylase) and 45- to 100-fold (isocitrate lyase and malate synthase) lower, indicating that the synthesis of the four enzymes is regulated by acetate in the growth medium. A comparative Northern (RNA) analysis of the C. glutamicum isocitrate lyase and malate synthase genes (aceA and aceB) and transcriptional cat fusion experiments revealed that aceA and aceB are transcribed as 1.6- and 2.7-kb monocistronic messages, respectively, and that the regulation of isocitrate lyase and malate synthase synthesis is exerted at the level of transcription from the respective promoters. Surprisingly, C. glutamicum mutants defective in either acetate kinase or phosphotransacetylase showed low specific activities of the other three enzymes (phosphotransacetylase, isocitrate lyase, and malate synthase or acetate kinase, isocitrate lyase, and malate synthase, respectively) irrespective of the presence or absence of acetate in the medium. This result and a correlation of a high intracellular acetyl coenzyme A concentration with high specific activities of isocitrate lyase, malate synthase, acetate kinase, and phosphotransacetylase suggest that acetyl coenzyme A or a derivative thereof may be a physiological trigger for the genetic regulation of enzymes involved in acetate metabolism of C. glutamicum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002030050497
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Identification and transcriptional analysis of the dapB-ORF2- dapA-ORF4 operon of Corynebacterium glutamicum, encoding two enzymes involved in L-lysine synthesis (1997)
    Springer
    Biotechnology letters 19 (1997), S. 1113-1117 
    Details
    ISSN: 1573-6776
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The dapA gene encoding dihydrodipicolinate synthase of Corynebacterium glutamicum is pivotal for high-level L-lysine production. The entire dapB-ORF2- dapA-ORF4 gene cluster was cloned, its sequence of 5907 bp completed, and a Northern analysis was performed. Whereas deletion of ORF2 had no detectable consequences for the cell, the interruption of ORF4 resulted (i) in a decreased growth rate, (ii) an increased specific activity of the diaminopimelate decarboxylase, and (iii) a decreased specific activity of the diaminopimelate dehydrogenase. Based on these physiological features, and structural features of the ORF4 encoded protein shared with the initiation factor IF2 of Streptococcus faecium, we hypothesize that ORF4 is part of a transcriptional control element in C. glutamicum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018444727849
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...