Determination of the cell doubling-time distribution from culture growth-rate data

1965 ◽  
Vol 9 (2) ◽  
pp. 297-302 ◽  
Author(s):  
Henry R. Hirsch ◽  
Joseph Engelberg
Keyword(s):  
Growth Rate ◽  
Time Distribution ◽  
Doubling Time ◽  
Rate Data ◽  
Cell Doubling Time ◽  
Culture Growth

scholarly journals Elimination of [PSI+] Prion and Influence on Yeast Cell Growth

2022 ◽  
Author(s):  
Justina Versockienė ◽  
Neda Jonutytė-Trembo ◽  
Vitalij Novickij ◽  
Eglė Lastauskienė
Keyword(s):  
Cell Growth ◽  
Optical Density ◽  
Doubling Time ◽  
Prion Proteins ◽  
Growth Dynamics ◽  
Model System ◽  
Cell Doubling Time ◽  
Culture Growth ◽  
Positive Effect

Abstract Background Prions are proteinaceous infectious particles that act as pathogens and cause the development of lethal neurodegenerative diseases in humans and other animals. Yeast Saccharomyces cerevisiae is a widespread model system in which mechanisms of prion induction and elimination have been identified. New and safe substances and methods are being sought to cure cells of prion proteins. It is particularly important that by treating cells from prions and restoring them from the [PSI+] to the [psi−] form, the primary growth of the cells is restored. One of the main objectives of this study was to determine the growth dynamics of S. cerevisiae cells with different [PSI+] prion variants, cells that have lost [PSI+] prion variants, and cells that never had [PSI+] prion variants. Results In this research, we applied GuHCl and combined GuHCl and PEF treatment against [PSI+] prion. We evaluated cells culture growth dynamics – optical density and doubling time and determined that method of [PSI+] prion elimination does not affect cell doubling time. Also, we found that both elimination methods affect the optical density reached by [psi−] cells. However, the cells in which the [PSI+] prion has been eliminated by GuHCl alone are able to reach the same optical density as unaffected [psi−] cells and higher optical density than the affected [psi−] cells by GuHCl alone. Conclusions These findings indicate the potential long-term positive effect of [PSI+] prion on cell growth, which persists after [PSI+] removal.

CULTURAL AND BIOCHEMICAL PARAMETERS OF TWO MICROALGAE, PHAEODACTYLUM TRICORNUTUM AND TETRASELMIS SUECIACA, IN CUMULATIVE CULTURES

2020 ◽  
pp. 54-65
Author(s):  
N.N. Kovalev ◽  
◽  
S.E. Leskova ◽  
E.V. Mikheev ◽  
Yu.M. Pozdnyakova ◽  
...  
Keyword(s):  
Growth Rate ◽  
Biochemical Parameters ◽  
Phaeodactylum Tricornutum ◽  
Culture Medium ◽  
Cell Growth Rate ◽  
Cumulative Culture ◽  
Microalgal Biomass ◽  
Culture Growth ◽  
Microalgal Species

A comparative study of cultural and biochemical parameters of two microalgal species, Tetraselmis sueciaca and Phaeodactylum tricornutum, was performed. Cell density in the storage culture was 2.88 million cells per one ml for T. sueciaca and 20.37 million cells per one ml for Ph. tricornutum. As shown, determination of op-tical density of the culture medium is a more objective characteristic of the cumulative culture growth. For T. sueciaca, cell growth rate during the course of experiment made 400% and for Ph. tricornutum – 700%. Dif-ference in the chemical composition of microalgal biomass was revealed. The microalgae did not differ in their energy value. The prospects of cumulative culture of microalgae in mariculture farms are discussed.

scholarly journals New Kinetic Spectrophotometric Method for Determination of Folic Acid in Pharmaceutical Formulations

2015 ◽  
Vol 50 ◽  
pp. 169-178
Author(s):  
Mouhammed Khateeb ◽  
Basheer Elias ◽  
Fatema Al Rahal
Keyword(s):  
Folic Acid ◽  
Spectrophotometric Method ◽  
Pharmaceutical Formulations ◽  
Fixed Time ◽  
Rate Data ◽  
Sulfuric Acid Medium ◽  
Significant Difference ◽  
Kinetic Spectrophotometric ◽  
Comparison Of The Results

A simple and sensitive kinetic spectrophotometric method has been developed for the determination of folic acid (FA) in bulk and pharmaceutical Formulations. The method is based on the oxidation of FA by Fe (III) in sulfuric acid medium. Fe (III) subsequently reduces to Fe (II) which is coupled with potassium ferricyanide to form Prussian blue. The reaction is followed spectrophotometrically by measuring the increase in absorbance at λmax 725 nm. The rate data and fixed time methods were adopted for constructing the calibration curves. The linearity range was found to be 1–20 μg mL-1 for each method. The correlation coefficient was 0.9978 and 0.9993, and LOD was found to be 0.91 and 0.09 μg mL-1 for rate data and fixed time methods, respectively. The proposed method has been successfully applied to the determination of FA in formulations with no interference from the excipients. Statical comparison of the results shows that there is no significant difference between the proposed and pharmacopoeial methods

Determination of the Growth Rate of Hydrothermally Synthesised ZnO2 Crystallites

2017 ◽  
Vol 50 ◽  
pp. 41-47 ◽  
Author(s):  
Martin Egblewogbe ◽  
Garu Gebreyesus ◽  
Samuel A. Atarah
Keyword(s):  
Growth Rate ◽  
Zinc Acetate Dihydrate ◽  
Hydrothermal Process ◽  
Growth Rate Constant ◽  
Acetate Dihydrate ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Zinc Peroxide

Powders consisting of nanoparticles of zinc peroxide were prepared via a simple hydrothermal process using zinc acetate dihydrate and hydrogen peroxide precursors. The size of the crystallites was determined using x-ray powder diffraction. Over a period of 5 hours the crystallite radius increased from 4 nm – 9 nm at a temperature of 68 °C ± 5 °C, with growth rate constant of 0.23 nm3 min−1 calculated using the Lifshitz, Slyozov, and Wagner model. The powders were further characterised with High Resolution Transmission Electron Microscopy, Energy Dispersive X-ray analysis, and Small Angle X-ray Scattering, showing well-crystallised ZnO2 nanoparticles.

scholarly journals The ameliorative effect of selenium on Azolla caroliniana grown under UV-B stress

2015 ◽  
Vol 95 (1) ◽  
pp. 20-26 ◽  
Author(s):  
E.M. Mostafa ◽  
A.M.A. Hassan
Keyword(s):  
Growth Rate ◽  
Protein Content ◽  
Doubling Time ◽  
The Other ◽  
Total Glutathione ◽  
Nutrient Media ◽  
Relative Growth ◽  
Other Hand ◽  
Ameliorative Effect ◽  
Glutathione Redox

Exposure ofAzollaplants to UV-B radiation for 6 h resulted in a decrease in biomass and relative growth rate (RGR), which coincided with an increase in doubling time (DT) as compared with the control. Also, the protein content decreased. On the other hand, hydrogen peroxyde (H2O2) and malondialdehyde (MDA) accumulated significantly in UV-treatedAzollaplants. Conversely, the addition of selenium (Se) at 1 ppm resulted in a significant increase in biomass and protein content of untreated and UV-treatedAzollaplants, and a significant reduction in both H2O2and MDA. Moreover, the addition of Se to UV-treated and untreatedAzollaplants resulted in a significant increase in total ascorbate and total glutathione (GSH) contents compared with the control and UV-stressedAzollaplants. Also, glutathione redox potential (GSH/TG) increased significantly in UV-treatedAzollaplants in the presence of Se. There also was a significant increase (38%) in ascorbate peroxidase (APX) activity in UV-treated plants compared with the control. APX activity in the presence of Se did not change significantly compared with the control. Glutathione reductase (GR) activity increased significantly in UV-treatedAzolla, while glutathione peroxidase (GSH-PX) activity did not. On the other hand, both GSH-PX and GR activity in untreated and UV-treatedAzollaplants were significantly enhanced by the application of Se to the nutrient media at a concentration of 1 ppm. Therefore, we can conclude that Se protectsAzollaplants from UV-B stress.

Interpretation of crystal growth rate data using a modified two-step model

1992 ◽  
Vol 123 (1-2) ◽  
pp. 236-246 ◽  
Author(s):  
Clifford Y. Tai ◽  
Chuen-Song Cheng ◽  
Yuen-Chen Huang
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Crystal Growth Rate ◽  
Rate Data ◽  
Step Model
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