X-ray microanalysis of HeLa S3 Cells. I. Instrumental calibration and analysis of randomly growing cultures

1983 ◽  
Vol 60 (1) ◽  
pp. 217-229
Author(s):  
A. Warley ◽  
J. Stephen ◽  
A. Hockaday ◽  
T.C. Appleton
Keyword(s):  
Cell Damage ◽  
Linear Calibration ◽  
Photometric Analysis ◽  
Sodium Potassium ◽  
X Ray ◽  
Potassium Tartrate ◽  
Freeze Dried ◽  
Hela S3 ◽  
Low K ◽  
Hela S3 Cells

Cryo-ultramicrotomy and X-ray microanalysis were used to study the elemental composition of HeLa S3 cells. Quantitation was achieved by reference to elemental standards of known concentration made up in 25% gelatin. Analysis of standards showed linear calibration for each of the elements studied: Na, P, S, Cl, K. Standardization was validated by comparing flame-photometric analysis of gelatin containing sodium potassium tartrate with that of X-ray microanalysis. Freeze-dried sections of cells showed good morphology and analysis of whole sections of the cells showed that K/Na varied in individual cells. Low K/Na could not be ascribed to cell damage or to the sequestering of Na in any particular subcompartment of the cells. Treatment with ouabain caused changes in levels of all the elements studied and resulted in a low K/Na ratio in all cells.

X-ray microanalysis of HeLa S3 cells. II. Analysis of elemental levels during the cell cycle

1983 ◽  
Vol 62 (1) ◽  
pp. 339-350
Author(s):  
A. Warley ◽  
J. Stephen ◽  
A. Hockaday ◽  
T.C. Appleton
Keyword(s):  
Cell Cycle ◽  
Monovalent Cation ◽  
The Other ◽  
G1 Phase ◽  
Sodium Potassium ◽  
X Ray ◽  
Cation Concentration ◽  
Cell Compartments ◽  
Hela S3 ◽  
Hela S3 Cells

HeLa S3 cells were synchronized using hydroxyurea. Cryoultramicrotomy and X-ray microanalysis were used to study changes occurring in concentrations of elements during the cell cycle of the synchronized cells. Three subcellular compartments were studied: cytoplasm, nucleus and nucleolus. Potassium concentrations showed little fluctuation in all of the cell compartments during the cell cycle. Sodium concentrations increased during S. and M phases, returning to lower levels in the G1 phase. Chlorine concentrations were highest during the S and G2 phases. At all stages of the cell cycle respective concentrations of potassium, sodium, sulphur and chlorine were similar in the cytoplasm and nucleus. Concentrations of phosphorus increased in the nucleus during S, G2 and M, and also showed fluctuations in the nucleolus during the cycle; these were not seen in the cytoplasm. In S, M and M/G1 sodium concentrations were highest in the nucleolus compared with the other compartments. In the cytoplasm these changes resulted in an increase in total monovalent cation concentration (i.e. sodium + potassium) during S, G2 and M, which returned to base levels after mitosis. This increase in monovalent cation concentration is due almost entirely to the increase in sodium, with little change occurring in the concentration of potassium.

scholarly journals Slow cooling of protein crystals

2009 ◽  
Vol 42 (5) ◽  
pp. 944-952 ◽  
Author(s):  
Matthew Warkentin ◽  
Robert E. Thorne
Keyword(s):  
Ice Nucleation ◽  
Glycerol Solution ◽  
X Ray Diffraction ◽  
Slow Cooling ◽  
Sodium Potassium ◽  
X Ray ◽  
Structure And Dynamics ◽  
Potassium Tartrate ◽  
Flash Cooling ◽  
Diffraction Patterns

Cryoprotectant-free thaumatin crystals have been cooled from 300 to 100 K at a rate of 0.1 K s−1– 103–104times slower than in conventional flash cooling – while continuously collecting X-ray diffraction data, so as to follow the evolution of protein lattice and solvent properties during cooling. Diffraction patterns show no evidence of crystalline ice at any temperature. This indicates that the lattice of protein molecules is itself an excellent cryoprotectant, and with sodium potassium tartrate incorporated from the 1.5 Mmother liquor ice nucleation rates are at least as low as in a 70% glycerol solution. Crystal quality during slow cooling remains high, with an average mosaicity at 100 K of 0.2°. Most of the mosaicity increase occurs above ∼200 K, where the solvent is still liquid, and is concurrent with an anisotropic contraction of the unit cell. Near 180 K a crossover to solid-like solvent behavior occurs, and on further cooling there is no additional degradation of crystal order. The variation ofBfactor with temperature shows clear evidence of a protein dynamical transition near 210 K, and at lower temperatures the slope dB/dTis a factor of 3–6 smaller than has been reported for any other protein. These results establish the feasibility of fully temperature controlled studies of protein structure and dynamics between 300 and 100 K.

scholarly journals Modification of X-Ray-Induced Killing of HeLa S3 Cells by Inhibitors of DNA Synthesis

1967 ◽  
Vol 7 (6) ◽  
pp. 779-795 ◽  
Author(s):  
Barbara G. Weiss ◽  
L.J. Tolmach
Keyword(s):  
Dna Synthesis ◽  
X Ray ◽  
Hela S3 ◽  
Hela S3 Cells

Susceptibility of X-Ray-Arrested HeLa S3 Cells to Additional Arrest

1976 ◽  
Vol 66 (3) ◽  
pp. 649 ◽  
Author(s):  
L. J. Tolmach ◽  
T. D. Griffiths ◽  
R. W. Jones
Keyword(s):  
X Ray ◽  
Hela S3 ◽  
Hela S3 Cells

Age-Dependence of the X-Ray-Induced Deficiency in DNA Synthesis in HeLa S3 Cells during Generation 1

1975 ◽  
Vol 63 (3) ◽  
pp. 501 ◽  
Author(s):  
T. Dan Griffiths ◽  
L. J. Tolmach
Keyword(s):  
Dna Synthesis ◽  
Age Dependence ◽  
X Ray ◽  
Hela S3 ◽  
Hela S3 Cells

Delayed Expression of the X-Ray-Induced Depression of DNA Synthetic Rate in HeLa S3 Cells

1976 ◽  
Vol 66 (1) ◽  
pp. 76 ◽  
Author(s):  
B. K. Saha ◽  
L. J. Tolmach
Keyword(s):  
X Ray ◽  
Synthetic Rate ◽  
Hela S3 ◽  
Hela S3 Cells

scholarly journals X-ray Sensitivity of HeLa S3 Cells in the G2 Phase

1967 ◽  
Vol 7 (1) ◽  
pp. 77-94 ◽  
Author(s):  
Bozidar Djordjevic ◽  
L.J. Tolmach
Keyword(s):  
X Ray ◽  
Hela S3 ◽  
G2 Phase ◽  
Hela S3 Cells

scholarly journals Synthesis of the FePt nanosystem: comparison of the synthesis methods

2020 ◽  
Vol 64 (10) ◽  
pp. 33-39
Author(s):  
Nikita S. Zaharov ◽  
◽  
Anna N. Popova ◽  
Yury A. Zaharov ◽  
Olga V. Grishaeva ◽  
...  
Keyword(s):  
Hydrazine Hydrate ◽  
Sodium Tetrahydroborate ◽  
Fept Nanoparticles ◽  
Target Product ◽  
Nanosized Particles ◽  
X Ray Diffraction ◽  
Sodium Potassium ◽  
X Ray ◽  
Iron Platinum ◽  
Potassium Tartrate

In this work, using the example of the synthesis of nanoparticles of the mutual FePt system, obtained in an aqueous medium by the method of co-reduction of solutions of metal precursors, the effect of reducing agents is considered: an alkaline solution of hydrazine hydrate and sodium tetrahydroborate in combination with a stabilizer of sodium-potassium tartrate. The main characteristics of the obtained nanosized particles of the iron-platinum system were studied by means of a complex of physicochemical methods of analysis. The shape and morphology of the obtained nanosized particles were studied by transmission electron microscopy, phase analysis and X-ray structural parameters – by X-ray diffraction methods. It was approached to reveal the dependence of the particle size on the type of reducing agent used. It was found that nanosized FePt particles obtained with different reducing agents have similar physicochemical characteristics. The use of sodium tetrahydroborate, in the presence of a stabilizer sodium-potassium tartrate, allowed to obtain more dispersed particles with a size of 14.3±2.1 nm. FePt nanoparticles reduced by hydrazine hydrate were characterized by large sizes of 16.7±4.0 nm, and the particles form large dense agglomerates. Chemical analysis showed that when reducing with sodium tetrahydroborate, the target product contained 0.4 mol. % boron. When reducing FePt nanoparticles with hydrazine hydrate, it was found that the target product was contaminated with iron oxide, which was also confirmed by X-ray phase analysis. X-ray diffraction analysis showed that the iron-platinum nanosystem was represented by a solid-solution phase with a face-centred cubic lattice. The parameters of the crystal lattice were estimated, 3.908 Å and 3.894 Å, respectively, for FePt nanoparticles obtained using NaBH4 and N2H4∙H2O.

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