Steady Measurement of Glucose Metabolism of Hepatocyte

2007 ◽  
Author(s):  
Ryo Shirakashi ◽  
Tomomi Yoshida ◽  
Christophe Provin ◽  
Kiyoshi Takano ◽  
Yasuyuki Sakai ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Metabolic Rate ◽  
Flow Rate ◽  
Glucose Concentration ◽  
Culture Medium ◽  
Consumption Rate ◽  
Glucose Consumption ◽  
Artificial Organ ◽  
Glucose Consumption Rate ◽  
Number Of Cells

Production of hybrid artificial organs for implantation is one of the main topics of tissue engineering. A large organ consisting of soft tissues requires a high cell density, c.a. 108 cells/mL, to satisfy the same physiological metabolic rate per organ-volume as an organ in vivo. Therefore, the supply of oxygen and nutrition to all the cells composing the soft tissue is always critical problem for the in vitro artificial organ production. Energy metabolic rates, such as oxygen and glucose metabolism rate, of single cell at various temperatures are the basic data for designing the oxygen and nutrition transport in an artificial organ. It is reported that several conditions including pH, temperature, oxygen or glucose concentration have effects on energy metabolism, although these interactions are not clearly quantitatively measured mainly because of the problems of measuring systems. In this study, convenient method to measure glucose consumption rate of hepatocyte (HepG2 cell line) at different temperature and glucose concentration is proposed. A device for the measurement was developed which consists of a small closed chamber with an inlet and an outlet of culture medium at the both ends of the chamber. On the one side of the walls in the chamber, confluent HepG2 on a coverslip was installed. Culture medium supplemented with various concentration of glucose was supplied to the open flow chamber in a constant flow rate. The whole chamber was in a thermostatic bath to keep the temperature in the chamber constant. Glucose consumption rate can be calculated by measuring the difference between glucose concentration of inlet culture medium and outlet culture medium, the flow rate and the number of cells in the chamber. Enzymatic analysis using D-Glucose-HK allows quantification of the sample glucose concentration. The advantages of the proposed method include; 1) small number of cells is required for the measurement, c. a. 105cells, 2) the flow pattern and the glucose supply are in steady state. Especially the latter advantage made it possible to evaluate the effects of different conditions on the glucose consumption rate. Since the most of the metabolic rate were measured under unsteady state, conditions, such as pH, oxygen concentration and glucose concentration, were changed sometime drastically during the measurement. The results provided the several parameters of Michaelis-Menten kinetics at various temperatures.

Biofilm monitoring: a perfect solution in search of a problem

2003 ◽  
Vol 47 (5) ◽  
pp. 9-18 ◽  
Author(s):  
Z. Lewandowski ◽  
H. Beyenal
Keyword(s):  
Consumption Rate ◽  
Glucose Consumption ◽  
Data Interpretation ◽  
Integrated System ◽  
Glucose Consumption Rate ◽  
Biofilm Heterogeneity

The main problem with monitoring biofilms is data interpretation. Biofilm heterogeneity causes monitored parameters to vary from location to location in the same biofilm, and it is difficult to assess to what extent these variations are caused by biofilm heterogeneity and to what extent they reflect other properties of the biofilm. We have used the concept of discretized biofilms, which is an integrated system of biofilm monitoring and data interpretation, to assess the effect of biofilm heterogeneity on biofilm activity. Using this approach we have estimated that a heterogeneous biofilm can be ten times more active, in terms of glucose consumption rate, than a homogeneous biofilm of the same thickness but with uniformly distributed density.

Monitoring the Kinetics of Glucose Transfer across a Bioreactor Membrane with a Glucose Sensor

1989 ◽  
Vol 12 (8) ◽  
pp. 539-543 ◽  
Author(s):  
G. Velho ◽  
G. Reach
Keyword(s):  
Cell Culture ◽  
Flow Rate ◽  
Glucose Concentration ◽  
Culture Medium ◽  
Glucose Sensor ◽  
Hollow Fibers ◽  
Bioartificial Pancreas ◽  
Cell Compartment ◽  
Glucose Transfer ◽  
Kinetics Of

Bioreactors for cell culture, in which hollow fibers are sealed into a protective jacket, cells are seeded in the fibers’ outer surface and a culture medium circulates through the fibers, have been proposed as a bioartificial pancreas. We used a needle-type glucose sensor to study the kinetics of glucose transfer across the membrane of one such device. The glucose transfer was found to be dependent on the flow rate of the circulating medium, which suggests the involvement of an ultrafiltration flux across the membrane. The glucose concentration was heterogeneous within the cell compartment. This heterogeneity, and the delay in transmission of changes in glucose concentration from the circulating medium to the cell compartment, can be ascribed to the large volume of the compartment. The design of these bioreactors should therefore be modified, in order to meet the requirements of glucose transfer kinetics of a bioartificial pancreas.

scholarly journals Influence of static magnetic fields on S. cerevisae biomass growth

2007 ◽  
Vol 50 (3) ◽  
pp. 515-520 ◽  
Author(s):  
João B. Muniz ◽  
Milton Marcelino ◽  
Mauricio da Motta ◽  
Alexandre Schuler ◽  
Mauricy Alves da Motta
Keyword(s):  
Magnetic Fields ◽  
Consumption Rate ◽  
Cylindrical Tube ◽  
Glucose Consumption ◽  
Dry Weight ◽  
Biomass Growth ◽  
Glucose Consumption Rate ◽  
Static Magnetic Fields ◽  
Tube Reactor ◽  
Flow Intensity

Biomass growth of Saccharomyces cerevisiae DAUFPE-1012 was studied in eight batch fermentations exposed to steady magnetic fields (SMF) running at 23ºC (± 1ºC), for 24 h in a double cylindrical tube reactor with synchronic agitation. For every batch, one tube was exposed to 220mT flow intensity SMF, produced by NdFeB rod magnets attached diametrically opposed (N to S) magnets on one tube. In the other tube, without magnets, the fermentation occurred in the same conditions. The biomass growth in culture (yeast extract + glucose 2%) was monitored by spectrometry to obtain the absorbance and later, the corresponding cell dry weight. The culture glucose concentration was monitored every two hours so as the pH, which was maintained between 4 and 5. As a result, the biomass (g/L) increment was 2.5 times greater in magnetized cultures (n=8) as compared with SMF non-exposed cultures (n=8). The differential (SMF-control) biomass growth rate (135%) was slightly higher than the glucose consumption rate (130 %) leading to increased biomass production of the magnetized cells.

scholarly journals Overflow Metabolism in Escherichia coli during Steady-State Growth: Transcriptional Regulation and Effect of the Redox Ratio

2006 ◽  
Vol 72 (5) ◽  
pp. 3653-3661 ◽  
Author(s):  
G. N. Vemuri ◽  
E. Altman ◽  
D. P. Sangurdekar ◽  
A. B. Khodursky ◽  
M. A. Eiteman
Keyword(s):  
Escherichia Coli ◽  
Consumption Rate ◽  
Nadh Oxidase ◽  
Glucose Consumption ◽  
Tca Cycle ◽  
Overflow Metabolism ◽  
Glucose Consumption Rate ◽  
Redox Ratio ◽  
E Coli ◽  
Acetate Formation

ABSTRACT Overflow metabolism in the form of aerobic acetate excretion by Escherichia coli is an important physiological characteristic of this common industrial microorganism. Although acetate formation occurs under conditions of high glucose consumption, the genetic mechanisms that trigger this phenomenon are not clearly understood. We report on the role of the NADH/NAD ratio (redox ratio) in overflow metabolism. We modulated the redox ratio in E. coli through the expression of Streptococcus pneumoniae (water-forming) NADH oxidase. Using steady-state chemostat cultures, we demonstrated a strong correlation between acetate formation and this redox ratio. We furthermore completed genome-wide transcription analyses of a control E. coli strain and an E. coli strain overexpressing NADH oxidase. The transcription results showed that in the control strain, several genes involved in the tricarboxylic acid (TCA) cycle and respiration were repressed as the glucose consumption rate increased. Moreover, the relative repression of these genes was alleviated by expression of NADH oxidase and the resulting reduced redox ratio. Analysis of a promoter binding site upstream of the genes which correlated with redox ratio revealed a degenerate sequence with strong homology with the binding site for ArcA. Deletion of arcA resulted in acetate reduction and increased the biomass yield due to the increased capacities of the TCA cycle and respiration. Acetate formation was completely eliminated by reducing the redox ratio through expression of NADH oxidase in the arcA mutant, even at a very high glucose consumption rate. The results provide a basis for studying new regulatory mechanisms prevalent at reduced NADH/NAD ratios, as well as for designing more efficient bioprocesses.

Glucose consumption rate critically depends on redox state in Corynebacterium glutamicum under oxygen deprivation

2015 ◽  
Vol 99 (13) ◽  
pp. 5573-5582 ◽  
Author(s):  
Yota Tsuge ◽  
Kimio Uematsu ◽  
Shogo Yamamoto ◽  
Masako Suda ◽  
Hideaki Yukawa ◽  
...  
Keyword(s):  
Corynebacterium Glutamicum ◽  
Redox State ◽  
Consumption Rate ◽  
Glucose Consumption ◽  
Oxygen Deprivation ◽  
Glucose Consumption Rate

scholarly journals Intracellular Glucose Concentration in Derepressed Yeast Cells Consuming Glucose Is High Enough To Reduce the Glucose Transport Rate by 50%

1998 ◽  
Vol 180 (3) ◽  
pp. 556-562 ◽  
Author(s):  
Bas Teusink ◽  
Jasper A. Diderich ◽  
Hans V. Westerhoff ◽  
Karel van Dam ◽  
Michael C. Walsh
Keyword(s):  
Glucose Transport ◽  
Glucose Concentration ◽  
Glucose Consumption ◽  
Yeast Cells ◽  
Signal Molecule ◽  
Glucose Consumption Rate ◽  
Influx Rate ◽  
Primary Signal ◽  
Free Glucose ◽  
Intracellular Glucose

ABSTRACT In Saccharomyces cerevisiae cells exhibiting high-affinity glucose transport, the glucose consumption rate at extracellular concentrations above 10 mM was only half of the zerotrans-influx rate. To determine if this regulation of glucose transport might be a consequence of intracellular free glucose we developed a new method to measure intracellular glucose concentrations in cells metabolizing glucose, which compares glucose stereoisomers to correct for adhering glucose. The intracellular glucose concentration was 1.5 mM, much higher than in most earlier reports. We show that for the simplest model of a glucose carrier, this concentration is sufficient to reduce the glucose influx by 50%. We conclude that intracellular glucose is the most likely candidate for the observed regulation of glucose import and hence glycolysis. We discuss the possibility that intracellular glucose functions as a primary signal molecule in these cells.

Assay of the Glucose Consumption Rate in Liver with a Novel Colorimetric Method

2011 ◽  
Vol 7 (3) ◽  
pp. 195-201 ◽  
Author(s):  
Zhicai Zhang ◽  
Xin Li ◽  
Mingxia Chen ◽  
Wangli Shen
Keyword(s):  
Consumption Rate ◽  
Colorimetric Method ◽  
Glucose Consumption ◽  
Glucose Consumption Rate

Physiological implications of class IIa bacteriocin resistance in Listeria monocytogenes strains

Microbiology ◽  
2004 ◽  
Vol 150 (2) ◽  
pp. 335-340 ◽  
Author(s):  
Viveka Vadyvaloo ◽  
Jacky L. Snoep ◽  
John W. Hastings ◽  
Marina Rautenbach
Keyword(s):  
Growth Rate ◽  
Listeria Monocytogenes ◽  
Consumption Rate ◽  
Biomass Yield ◽  
Specific Growth ◽  
Glucose Consumption ◽  
Acid Fermentation ◽  
Lower Growth ◽  
Glucose Consumption Rate ◽  
Resistant Strains

High-level resistance to class IIa bacteriocins has been directly associated with the absent EIIABMan (MptA) subunit of the mannose-specific phosphoenolpyruvate-dependent phosphotransferase system (PTS) () in Listeria monocytogenes strains. Class IIa bacteriocin-resistant strains used in this study were a spontaneous resistant, L. monocytogenes B73-MR1, and a defined mutant, L. monocytogenes EGDe-mptA. Both strains were previously reported to have the EIIABMan PTS component missing. This study shows that these class IIa bacteriocin-resistant strains have significantly decreased specific growth and glucose consumption rates, but they also have a significantly higher growth yield than their corresponding wild-type strains, L. monocytogenes B73 and L. monocytogenes EGDe, respectively. In the presence of glucose, the strains showed a shift from a predominantly lactic-acid to a mixed-acid fermentation. It is here proposed that elimination of the EIIABMan in the resistant strains has caused a reduced glucose consumption rate and a reduced specific growth rate. The lower glucose consumption rate can be correlated to a shift in metabolism to a more efficient pathway with respect to ATP production per glucose, leading to a higher biomass yield. Thus, the cost involved in obtaining bacteriocin resistance, i.e. losing substrate transport capacity leading to a lower growth rate, is compensated for by a higher biomass yield.

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