Graphical evaluation of the kinetic parameters for bacterial growth

1969 ◽  
Vol 15 (10) ◽  
pp. 1201-1205 ◽  
Author(s):  
Frank E. Stratton ◽  
Perry L. McCarty
Keyword(s):  
Kinetic Parameters ◽  
Bacterial Growth ◽  
Graphical Method ◽  
Substrate Oxidation ◽  
Kinetic Rate ◽  
Substrate Use ◽  
Oxidation Curve ◽  
Estimate Rate ◽  
Rates Of Growth

Kinetic rate parameters governing the rates of growth and substrate use by bacteria may be estimated by a graphical method which makes use of the bacterial substrate oxidation curve. The method is simple and rapid and may be used to estimate rate parameters in situations in which more precise computer estimates cannot be performed.

Rapid determination of whole-body bicarbonate kinetics by use of a digital infusion

1984 ◽  
Vol 247 (4) ◽  
pp. R709-R716 ◽  
Author(s):  
C. S. Irving ◽  
W. W. Wong ◽  
W. M. Wong ◽  
T. W. Boutton ◽  
R. J. Shulman ◽  
...  
Keyword(s):  
Kinetic Parameters ◽  
Rapid Determination ◽  
Accurate Determination ◽  
Substrate Oxidation ◽  
Whole Body ◽  
Constant Infusion ◽  
External Control ◽  
Base Line ◽  
Oxidation Rates

Accurate determination of substrate oxidation rates from breath 13CO2 levels often requires information on the bicarbonate status of the subject. We have developed a rapid method to obtain a complete set of bicarbonate kinetic parameters, prime bicarbonate pools with 13C, clamp breath 13CO2 levels rapidly and accurately with predetermined ranges, and provide a steady base-line enrichment of 13C for a subsequent substrate oxidation measurement. The method consists of administering NaH13CO3 intravenously as a combination of a bolus dose, an exponentially decreasing infusion, and a constant infusion. A Harvard model 2729 microprocessor-controlled syringe pump was modified for external control and coupled to a Hewlett-Packard HP-85 desk-top computer to deliver the complex infusion. An infusion algorithm that would rapidly attain and maintain an increase of 50% 13C enrichment of breath CO2 was derived by using the SAAM-27 program to interrogate a three-compartmental model of bicarbonate kinetics in normal, fasted, resting adult subjects. When the method was tested on five adult fasted subjects who had rested for 1.5 h, plateau enrichments were achieved within 10–20 min. The bicarbonate pool sizes and kinetic parameters obtained by compartmental analysis of their 13CO2 data were used to obtain a refined infusion protocol, which resulted in more rapid attainment of plateau enrichments. If carried out immediately before a substrate oxidation test, the method can provide a complete description of bicarbonate kinetics for use in the compartmental and noncompartmental analysis of substrate catabolism.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Role of the kdpDE Regulatory Operon of Mycobacterium tuberculosis in Modulating Bacterial Growth in vitro

2021 ◽  
Vol 12 ◽  
Author(s):  
Moloko C. Cholo ◽  
Maborwa T. Matjokotja ◽  
Ayman G. Osman ◽  
Ronald Anderson
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Bacterial Growth ◽  
Deletion Mutant ◽  
Regulatory System ◽  
Growth Conditions ◽  
Knockout Mutant ◽  
Double Knockout ◽  
Uptake Efficiency ◽  
Rates Of Growth

Bacteria use K+-uptake transporters differentially for adaptation in varying growth conditions. In Mycobacterium tuberculosis, two K+-uptake systems, the Trk comprising the CeoB and CeoC proteins and the Kdp consisting of the two-component system (TCS), KdpDE and KdpFABC, have been characterized, but their selective utilization during bacterial growth has not been completely explored. In the current study, the roles of the M. tuberculosis KdpDE regulatory system alone and in association with the Trk transporters in bacterial growth were investigated by evaluating the growth of M. tuberculosis KdpDE-deletion and KdpDE/Trk (KT)-double knockout mutant strains in planktonic culture under standard growth conditions. The KT-double knockout mutant strain was first constructed using homologous recombination procedures and was evaluated together with the KdpDE-deletion mutant and the wild-type (WT) strains with respect to their rates of growth, K+-uptake efficiencies, and K+-transporter gene expression during planktonic growth. During growth at optimal K+ concentrations and pH levels, selective deletion of the TCS KdpDE (KdpDE-deletion mutant) led to attenuation of bacterial growth and an increase in bacterial K+-uptake efficiency, as well as dysregulated expression of the kdpFABC and trk genes. Deletion of both the KdpDE and the Trk systems (KT-double knockout) also led to severely attenuated bacterial growth, as well as an increase in bacterial K+-uptake efficiency. These results demonstrate that the KdpDE regulatory system plays a key role during bacterial growth by regulating K+ uptake via modulation of the expression and activities of both the KdpFABC and Trk systems and is important for bacterial growth possibly by preventing cytoplasmic K+ overload.

The Interaction of Obesity and Puberty on Substrate Utilization During Exercise: A Gender Comparison

2011 ◽  
Vol 23 (3) ◽  
pp. 411-431 ◽  
Author(s):  
Robert G. McMurray ◽  
Peter A. Hosick
Keyword(s):  
Oxidation Rate ◽  
Substrate Oxidation ◽  
Substrate Utilization ◽  
Normal Weight ◽  
Carbohydrate Oxidation ◽  
Metabolic Rates ◽  
Substrate Use ◽  
Gender Comparison ◽  
Oxidation Rates ◽  
Prepubertal Boys

The study evaluated the interactions of puberty and obesity on substrate oxidation of overweight girls (n = 38) and boys (N = 35; BMI > 85th percentile) matched for gender, age, and puberty (pre/pubertal) with normal weight girls and boys. Metabolic rates (VO2) were obtained during rest and at 4, 5.6 and 8 k/h. Carbohydrate oxidation rates (mg/kgFFM/min) adjusted for % predicted VO2max, were higher for prepubertal OW children than pubertal children (p < .03). Fat oxidation rates were higher for NW prepubertal boys compared with other boys. Results indicate that OW children, regardless of gender or pubertal status, increase their carbohydrate oxidation rate to compensate for higher than normal metabolic rates. The effects of obesity on the substrate use is marginally related to puberty.

scholarly journals A method for determining kinetic parameters at high enzyme concentrations

1982 ◽  
Vol 203 (1) ◽  
pp. 339-342 ◽  
Author(s):  
C J Halfman ◽  
F Marcus
Keyword(s):  
Enzyme Activity ◽  
Kinetic Parameters ◽  
Graphical Method ◽  
Free Ligand ◽  
Enzyme Concentration ◽  
Fructose 1,6 Bisphosphatase ◽  
High Enzyme ◽  
Substrate Inhibitor ◽  
The Relationship

A graphical method is described which allows determination of kinetic parameters when substrate, inhibitor or activator concentrations must be in the vicinity of the enzyme concentration and a significant fraction of ligand is bound. Velocity is measured at several ligand: enzyme ratios at two or more enzyme concentrations. Results are obtained in terms of free and bound ligand corresponding to particular velocities. The relationship between velocity and bound and free ligand may then be analysed by any desired plotting technique. Preknowledge of the reaction mechanism or experimental determination of Vmax. is not required. The relationship between ligand bound and enzyme activity need not be linear and the method is equally suitable for analysing co-operative as well as simple kinetics. Application of the method is demonstrated by analysis of the inhibition of fructose, 1,6-bisphosphatase by AMP.

scholarly journals Effect of Mg2+ and Mn2+ on isocitrate lyase, a non-essentially metal-ion-activated enzyme. A graphical approach for the discrimination of the model for activation

1991 ◽  
Vol 276 (1) ◽  
pp. 223-230 ◽  
Author(s):  
E Giachetti ◽  
P Vanni
Keyword(s):  
Kinetic Parameters ◽  
Metal Ion ◽  
Graphical Method ◽  
Isocitrate Lyase ◽  
Enzyme Reaction ◽  
Activation Mechanism ◽  
Simple Method ◽  
Suggested Approach ◽  
Graphical Approach ◽  
Substrate Complex

We describe a simple method for the analysis of activation systems in which a metal ion modifier may combine with either the enzyme or the substrate (or both) and the metal ion-substrate complex is the true substrate of the enzyme reaction. The suggested approach is essentially a ‘graphical’ method that both provides unbiased criteria for the choice of the activation mechanism and yields good rough estimates of the kinetic parameters. The procedure, tested on a variety of simulated models, produces appropriate and reliable results. Applying this treatment to isocitrate lyase, we confirmed the data previously reported for Mg2+ [Giachetti, Pinzauti, Bonaccorsi & Vanni (1988) Eur. J. Biochem. 172, 85-92], and we found that Mn2+ functions with the same mechanism as does Mg2+, but with quite different kinetic constants. In particular, its ratio of the Vmax, values of the activated and the non-activated enzyme is less than 1, and thus Mn2+ is to be considered an inhibitor rather than an activator.

Arrangement of Mitochondria in Spermatozoa of the Mexican Axolotl, Ambystoma Mexicanum

1973 ◽  
Vol 31 ◽  
pp. 626-627
Author(s):  
Ezzatollah Keyhani ◽  
Larry F. Lemanski ◽  
Sharon L. Lemanski
Keyword(s):  
Plasma Membrane ◽  
Sperm Motility ◽  
Substrate Oxidation ◽  
Ambystoma Mexicanum ◽  
Axial Filament ◽  
Mexican Axolotl ◽  
Middle Piece

Energy for sperm motility is provided by both glycolytic and respiratory pathways. Mitochondria are involved in the latter pathway and conserve energy of substrate oxidation by coupling to phosphorylation. During spermatogenesis, the mitochondria undergo extensive transformation which in many species leads to the formation of a nebemkem. The nebemkem subsequently forms into a helix around the axial filament complex in the middle piece of spermatozoa.Immature spermatozoa of axolotls contain numerous small spherical mitochondria which are randomly distributed throughout the cytoplasm (Fig. 1). As maturation progresses, the mitochondria appear to migrate to the middle piece region where they become tightly packed to form a crystalline-like sheath. The cytoplasm in this region is no longer abundant (Fig. 2) and the plasma membrane is now closely apposed to the outside of the mitochondrial layer.

Relation of Statistically Significant, Abnormal, and Typical WAIS-R VIQ-PIQ Discrepancies to Full Scale IQs

2000 ◽  
Vol 16 (2) ◽  
pp. 107-114 ◽  
Author(s):  
Louis M. Hsu ◽  
Judy Hayman ◽  
Judith Koch ◽  
Debbie Mandell
Keyword(s):  
Graphical Method ◽  
The United States ◽  
Full Scale ◽  
True Score ◽  
Absolute Value ◽  
Normative Population ◽  
The Us ◽  
The Mean ◽  
And Performance ◽  
Quadratic Models

Summary: In the United States' normative population for the WAIS-R, differences (Ds) between persons' verbal and performance IQs (VIQs and PIQs) tend to increase with an increase in full scale IQs (FSIQs). This suggests that norm-referenced interpretations of Ds should take FSIQs into account. Two new graphs are presented to facilitate this type of interpretation. One of these graphs estimates the mean of absolute values of D (called typical D) at each FSIQ level of the US normative population. The other graph estimates the absolute value of D that is exceeded only 5% of the time (called abnormal D) at each FSIQ level of this population. A graph for the identification of conventional “statistically significant Ds” (also called “reliable Ds”) is also presented. A reliable D is defined in the context of classical true score theory as an absolute D that is unlikely (p < .05) to be exceeded by a person whose true VIQ and PIQ are equal. As conventionally defined reliable Ds do not depend on the FSIQ. The graphs of typical and abnormal Ds are based on quadratic models of the relation of sizes of Ds to FSIQs. These models are generalizations of models described in Hsu (1996) . The new graphical method of identifying Abnormal Ds is compared to the conventional Payne-Jones method of identifying these Ds. Implications of the three juxtaposed graphs for the interpretation of VIQ-PIQ differences are discussed.

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