Cell Growth and By-Product Formation in a Pyruvate Kinase Mutant of E. coli

2001 ◽  
Vol 17 (4) ◽  
pp. 624-628 ◽  
Author(s):  
T. Zhu ◽  
C. Phalakornkule ◽  
R.R. Koepsel ◽  
M.M. Domach ◽  
M.M. Ataai
Keyword(s):  
Cell Growth ◽  
Pyruvate Kinase ◽  
Product Formation ◽  
E Coli

scholarly journals Application Of The Z And Laplace Transforms To Panification Yeast Production Using An Airlift Bioreactor

2020 ◽  
Author(s):  
Arnaldo Silva Oliveira ◽  
Juan C. B. Neto ◽  
Igor J. B. Santos ◽  
Edson R. Nucci
Keyword(s):  
Cell Growth ◽  
Product Formation ◽  
Laplace Transforms ◽  
Discrete Models ◽  
Average Error ◽  
Growth Substrate ◽  
Substrate Consumption ◽  
Yeast Saccharomyces Cerevisiae ◽  
Mathematical Techniques ◽  
Discrete Time Models

Abstract The Z- and Laplace transforms are mathematical techniques applied to solve difference equations and differential equations, respectively. Mathematical models used to describe cell growth, substrate consumption and product formation in bioprocesses can be represented by these types of equations. Thus, in this work, the fermentation process of the yeast Saccharomyces cerevisiae was modeled using different models from the literature, and the Z- and Laplace transforms were applied to solve the equations. Once the equations were solved, the models were represented in state space and simulated in Octave® software. Finally, the models were compared to experimental data from previous studies and to each other. Verhulst was the model that best described the process, with an average error of 4.74% for cell growth and 13.9% for substrate consumption. This work is unprecedented since no works that use the Z transform and discrete models for the representation of fermentation of this yeast were found in the literature. Even more importantly, this work proved that discrete-time models can be applied to bioprocesses with the same precision as continuous-time models.

scholarly journals Staphylococcus aureus MazF Specifically Cleaves a Pentad Sequence, UACAU, Which Is Unusually Abundant in the mRNA for Pathogenic Adhesive Factor SraP

2009 ◽  
Vol 191 (10) ◽  
pp. 3248-3255 ◽  
Author(s):  
Ling Zhu ◽  
Koichi Inoue ◽  
Satoshi Yoshizumi ◽  
Hiroshi Kobayashi ◽  
Yonglong Zhang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Cell Growth ◽  
Bioinformatics Analysis ◽  
Human Tissues ◽  
Regulatory Relationship ◽  
E Coli ◽  
Pathogenic Factors ◽  
Inhibit Cell Growth ◽  
Adhesive Factor

ABSTRACT Escherichia coli mRNA interferases, such as MazF and ChpBK, are sequence-specific endoribonucleases encoded by toxin-antitoxin (TA) systems present in its genome. A MazF homologue in Staphylococcus aureus (MazFSa) has been shown to inhibit cell growth when induced in E. coli. Here, we determined the cleavage site for MazFSa with the use of phage MS2 RNA as a substrate and CspA, an RNA chaperone, which prevents the formation of secondary structures in the RNA substrate. MazFSa specifically cleaves the RNA at a pentad sequence, U↓ACAU. Bioinformatics analysis revealed that this pentad sequence is significantly abundant in several genes, including the sraP gene in the S. aureus N315 strain. This gene encodes a serine-rich protein, which is known to play an important role in adhesion of the pathogen to human tissues and thus in endovascular infection. We demonstrated that the sraP mRNA became extremely unstable in comparison with the ompA mRNA only when MazFSa was induced in E. coli. Further bioinformatics analysis indicated that the pentad sequence is also significantly abundant in the mRNAs for all the pathogenic factors in S. aureus. This observation suggests a possible regulatory relationship between the MazEFSa TA module and the pathogenicity in S. aureus.

scholarly journals Microbial Synthesis of Non-Natural Anthraquinone Glucosides Displaying Superior Antiproliferative Properties

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2171 ◽  
Author(s):  
Trang Nguyen ◽  
Ramesh Pandey ◽  
Prakash Parajuli ◽  
Jang Han ◽  
Hye Jung ◽  
...  
Keyword(s):  
Cell Growth ◽  
Biological Activities ◽  
Uterine Cervical Cancer ◽  
Cell Growth Inhibition ◽  
Microbial Synthesis ◽  
E Coli ◽  
Anticancer Effects ◽  
Naturally Occurring ◽  
Spectroscopic Analyses ◽  
Proliferative Assay

Anthraquinones, naturally occurring bioactive compounds, have been reported to exhibit various biological activities, including anti-inflammatory, antiviral, antimicrobial, and anticancer effects. In this study, we biotransformed three selected anthraquinones into their novel O-glucoside derivatives, expressing a versatile glycosyltransferase (YjiC) from Bacillus licheniformis DSM 13 in Escherichia coli. Anthraflavic acid, alizarin, and 2-amino-3-hydroxyanthraquinone were exogenously fed to recombinant E. coli as substrate for biotransformation. The products anthraflavic acid-O-glucoside, alizarin 2-O-β-d-glucoside, and 2-amino-3-O-glucosyl anthraquinone produced in the culture broths were characterized by various chromatographic and spectroscopic analyses. The comparative anti-proliferative assay against various cancer cells (gastric cancer-AGS, uterine cervical cancer-HeLa, and liver cancer-HepG2) were remarkable, since the synthesized glucoside compounds showed more than 60% of cell growth inhibition at concentrations ranging from ~50 μM to 100 μM. Importantly, one of the synthesized glucoside derivatives, alizarin 2-O-glucoside inhibited more than 90% of cell growth in all the cancer cell lines tested.

scholarly journals Flexible Metabolism and Suppression of Latent Enzymes Are Important forEscherichia coliAdaptation to Diverse Environments within the Host

2019 ◽  
Vol 201 (16) ◽  
Author(s):  
Christopher J. Alteri ◽  
Stephanie D. Himpsl ◽  
Allyson E. Shea ◽  
Harry L. T. Mobley
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Pyruvate Kinase ◽  
Tricarboxylic Acid Cycle ◽  
Financial Burden ◽  
Content Type ◽  
Bacterial Physiology ◽  
E Coli ◽  
Growth Requirements ◽  
Tract Infections

ABSTRACTBacterial metabolism is necessary for adaptation to the host microenvironment. Flexible metabolic pathways allow uropathogenicEscherichia coli(UPEC) to harmlessly reside in the human intestinal tract and cause disease upon extraintestinal colonization.E. coliintestinal colonization requires carbohydrates as a carbon source, while UPEC extraintestinal colonization requires gluconeogenesis and the tricarboxylic acid cycle. UPEC containing disruptions in two irreversible glycolytic steps involving 6-carbon (6-phosphofructokinase;pfkA) and 3-carbon (pyruvate kinase;pykA) substrates have no fitness defect during urinary tract infection (UTI); however, both reactions are catalyzed by isozymes: 6-phosphofructokinases Pfk1 and Pfk2, encoded bypfkAandpfkB, and pyruvate kinases Pyk II and Pyk I, encoded bypykAandpykF. UPEC strains lacking one or both phosphofructokinase-encoding genes (pfkBandpfkA pfkB) and strains lacking one or both pyruvate kinase genes (pykFandpykA pykF) were investigated to determine their regulatory roles in carbon flow during glycolysis by examining their fitness during UTI andin vitrogrowth requirements. Loss of a single phosphofructokinase-encoding gene has no effect on fitness, while thepfkA pfkBdouble mutant outcompeted the parental strain in the bladder. A defect in bladder and kidney colonization was observed with loss ofpykF, while loss ofpykAresulted in a fitness advantage. ThepykA pykFmutant was indistinguishable from wild-typein vivo, suggesting that the presence of Pyk II rather than the loss of Pyk I itself is responsible for the fitness defect in thepykFmutant. These findings suggest thatE. colisuppresses latent enzymes to survive in the host urinary tract.IMPORTANCEUrinary tract infections are the most frequently diagnosed urologic disease, with uropathogenicEscherichia coli(UPEC) infections placing a significant financial burden on the health care system by generating more than two billion dollars in annual costs. This, in combination with steadily increasing antibiotic resistances to present day treatments, necessitates the discovery of new antimicrobial agents to combat these infections. By broadening our scope beyond the study of virulence properties and investigating bacterial physiology and metabolism, we gain a better understanding of how pathogens use nutrients and compete within host microenvironments, enabling us to cultivate new therapeutics to exploit and target pathogen growth requirements in a specific host environment.

scholarly journals Decoupling Protein Production from Cell Growth Enhances the Site-Specific Incorporation of Noncanonical Amino Acids in E. coli

2020 ◽  
Vol 9 (11) ◽  
pp. 3052-3066
Author(s):  
Meritxell Galindo Casas ◽  
Patrick Stargardt ◽  
Juergen Mairhofer ◽  
Birgit Wiltschi
Keyword(s):  
Amino Acids ◽  
Cell Growth ◽  
Protein Production ◽  
Noncanonical Amino Acids ◽  
Site Specific ◽  
E Coli

Sublethal acid stress and uncoupling effects on cell growth and product formation in Xanthomonas campestris cultures

2002 ◽  
Vol 12 (3) ◽  
pp. 181-192 ◽  
Author(s):  
M.Eugénia Esgalhado ◽  
Ana Teresa Caldeira ◽  
J.Carlos Roseiro ◽  
A.Nick Emery
Keyword(s):  
Cell Growth ◽  
Xanthomonas Campestris ◽  
Acid Stress ◽  
Product Formation

scholarly journals In Vivo Modulation of a DnaJ Homolog, CbpA, by CbpM

2007 ◽  
Vol 189 (9) ◽  
pp. 3635-3638 ◽  
Author(s):  
Matthew R. Chenoweth ◽  
Nancy Trun ◽  
Sue Wickner
Keyword(s):  
Escherichia Coli ◽  
Cell Growth ◽  
Stationary Phase ◽  
Specific Inhibitor ◽  
Vitro Activity ◽  
In Vitro Activity ◽  
E Coli ◽  
Hsp70 Chaperone

ABSTRACT CbpA, an Escherichia coli DnaJ homolog, can function as a cochaperone for the DnaK/Hsp70 chaperone system, and its in vitro activity can be modulated by CbpM. We discovered that CbpM specifically inhibits the in vivo activity of CbpA, preventing it from functioning in cell growth and division. Furthermore, we have shown that CbpM interacts with CbpA in vivo during stationary phase, suggesting that the inhibition of activity is a result of the interaction. These results reveal that the activity of the E. coli DnaK system can be regulated in vivo by a specific inhibitor.

The interaction of silver ions and hydrogen peroxide in the inactivation of E. coli: a preliminary evaluation of a new long acting residual drinking water disinfectant

1995 ◽  
Vol 31 (5-6) ◽  
pp. 123-129 ◽  
Author(s):  
Rami Pedahzur ◽  
Ovadia Lev ◽  
Badri Fattal ◽  
Hillel I. Shuval
Keyword(s):  
Hydrogen Peroxide ◽  
Drinking Water ◽  
Distribution Systems ◽  
Residual Effect ◽  
Silver Ions ◽  
Product Formation ◽  
Preliminary Evaluation ◽  
E Coli ◽  
The Usa ◽  
K 12

The inactivation efficiencies of silver ions, hydrogen peroxide and their combination was studied as part of a performance evaluation of the combined disinfectant for drinking water applications. The major advantages of such combined disinfectant include, low toxicity of its components, long lasting residual effect and low disinfection by product formation. Specific strains of E. coli (E. coli-B (SR-9) and E. coli K-12) were used in this study as target microorganisms and the separate and combined inactivation efficiencies of silver and hydrogen peroxide were evaluated at different concentrations and exposure durations. Both, silver and hydrogen peroxide exhibited a significant inactivation performance even at concentrations that do not pose any health risk according to the EEC, WHO and the USEPA (the USEPA Maximum Contaminant Level (MCL) of silver is 90 ppb, and currently, there is no MCL for hydrogen peroxide but it is approved as a food additive in the USA). Combinations of 1:1000 silver:hydrogen peroxide (w) exhibited higher inactivation performance as compared with each of the disinfectants alone and in some cases a synergistic effect was observed, i.e., the combined disinfectant exhibited higher inactivation performance than the sum of the inactivation levels of the separate disinfectants. Thus, for example, one hour exposure to 30 ppb silver, 30 ppm hydrogen peroxide and their combination yielded 2.87, 0.65 and 5 logs of inactivation respectively. While the rate of inactivation shown by this combined disinfectant, now available commercially in a stabilized formulation is relatively slow, it may well hold promise as a secondary disinfectant providing long lasting residuals and biofilm control required for distribution systems. Its disinfection action may be similar to chloramines, the use of which has been recently outlawed in France and in Germany and which are now under careful scrutiny in other countries due to the formation of undesirable by-products.

scholarly journals Asymmetric Whole-Cell Bio-Reductions of (R)-Carvone Using Optimized Ene Reductases

Molecules ◽  
2019 ◽  
Vol 24 (14) ◽  
pp. 2550 ◽  
Author(s):  
Christoph Mähler ◽  
Christian Burger ◽  
Franziska Kratzl ◽  
Dirk Weuster-Botz ◽  
Kathrin Castiglione
Keyword(s):  
Formation Rate ◽  
Product Formation ◽  
Regeneration System ◽  
Initial Product ◽  
Whole Cell ◽  
Stirred Tank Reactors ◽  
E Coli ◽  
Space Time Yield ◽  
Product Formation Rate ◽  
Site Selective

(2R,5R)-dihydrocarvone is an industrially applied building block that can be synthesized by site-selective and stereo-selective C=C bond bio-reduction of (R)-carvone. Escherichia coli (E. coli) cells overexpressing an ene reductase from Nostoc sp. PCC7120 (NostocER1) in combination with a cosubstrate regeneration system proved to be very effective biocatalysts for this reaction. However, the industrial applicability of biocatalysts is strongly linked to the catalysts’ activity. Since the cell-internal NADH concentrations are around 20-fold higher than the NADPH concentrations, we produced E. coli cells where the NADPH-preferring NostocER1 was exchanged with three different NADH-accepting NostocER1 mutants. These E. coli whole-cell biocatalysts were used in batch operated stirred-tank reactors on a 0.7 l-scale for the reduction of 300 mM (R)-carvone. 287 mM (2R,5R)-dihydrocarvone were formed within 5 h with a diasteromeric excess of 95.4% and a yield of 95.6%. Thus, the whole-cell biocatalysts were strongly improved by using NADH-accepting enzymes, resulting in an up to 2.1-fold increased initial product formation rate leading to a 1.8-fold increased space-time yield when compared to literature.

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