STUDY OF SOME FACTORS THAT AFFECT THE DISTRIBUTION OF NUCLEAR VOLUMES IN PREPARATIONS OF RAT LIVER NUCLEI

1967 ◽  
Vol 45 (7) ◽  
pp. 1175-1183 ◽  
Author(s):  
Roberto Umaña
Keyword(s):  
Rat Liver ◽  
Dna Content ◽  
Direct Relationship ◽  
Magnesium Ion ◽  
Homogenization Procedure ◽  
Ion Concentrations ◽  
Ph Values ◽  
Sucrose Solutions ◽  
Liver Nuclei ◽  
Calcium And Magnesium

The effect of the homogenization procedure, the centrifugation scheme, and the composition of the suspension medium on the distribution of nuclear volumes has been studied.It has been shown that the Waring Blendor not only destroys a greater number of the nuclei during homogenization, but also that this destruction is a selective one. At neutral pH values, no direct relationship appears to exist between the DNA content of the nuclei and their density. For this reason, purification in concentrated sucrose solutions produces a selective loss of the lighter nuclei, which includes small diploid stromal nuclei and some of the larger polyploid type of parenchymal nuclei.The study of the effect of increasing the calcium and magnesium ion concentrations (from 0.001 to 0.005 M) on the nuclear distribution showed that these ions produce a selective shrinkage and condensation of the nuclei, probably through different mechanisms.

scholarly journals The fractionation of nuclei from mammalian cells by zonal centrifugation

1968 ◽  
Vol 109 (1) ◽  
pp. 127-135 ◽  
Author(s):  
I R Johnston ◽  
A P Mathias ◽  
F. Pennington ◽  
D. Ridge
Keyword(s):  
Rat Liver ◽  
Mammalian Cells ◽  
Mouse Liver ◽  
The Other ◽  
Slow Speed ◽  
Adult Rats ◽  
Sucrose Solutions ◽  
Liver Nuclei ◽  
Effect Of Age ◽  
Zonal Rotor

1. Purified liver nuclei from adult rats separate into two main zones when centrifuged in the slow-speed zonal rotor. One zone contains diploid nuclei, the other tetraploid. 2. The effect of age on the pattern of rat liver ploidy was examined. Tetraploid nuclei are virtually absent from young animals. They increase in proportion steadily with age. Partial hepatectomy disturbs the pattern of ploidy. 3. The zonal centrifuge permits the separation of diploid, tetraploid, octaploid and hexadecaploid nuclei from mouse liver. 4. Rat liver nuclei are isopycnic with sucrose solutions of density 1·35 at 5°.

Visualization of Charged Groups on the Surface of Rat Liver Nuclei

1974 ◽  
Vol 16 (3) ◽  
pp. 665-675
Author(s):  
ISMO VIRTANEN ◽  
JORMA WARTIOVAARA
Keyword(s):  
Rat Liver ◽  
Plasma Membranes ◽  
Iron Hydroxide ◽  
Nuclear Surface ◽  
Colloidal Iron ◽  
Rat Liver Nuclei ◽  
Ph Values ◽  
Liver Nuclei ◽  
Pre Treatment ◽  
Anionic Groups

Anionic groups on the outer surfaces of isolated rat liver nuclei were rendered visible in the electron microscope by staining with colloidal iron hydroxide at different pH values. At pH 1.8 the nuclei did not adsorb particles of stain, although plasma membranes left in the same preparation showed heavy labelling. After pretreatment with neuraminidase at pH 6 the plasma membranes were no longer stained. At pH 3.0 the nuclear surfaces also stained intensely. The staining pattern acquired at this pH did not appear to be changed by neuraminidase pre-treatment. With the staining method used, rat liver nuclear surfaces seemed to have no exposed sialic acid under isolation conditions which preserve the nuclear membranes and leave the ribosomes attached to the nuclear surface. However, at higher pH values other anionic groups seem to become dissociated and are stained with colloidal iron hydroxide.

scholarly journals Changes in Sodium, Calcium, and Magnesium Ion Concentrations That Inhibit Geobacillus Biofilms Have No Effect on Anoxybacillus flavithermus Biofilms

2015 ◽  
Vol 81 (15) ◽  
pp. 5115-5122 ◽  
Author(s):  
B. Somerton ◽  
D. Lindsay ◽  
J. Palmer ◽  
J. Brooks ◽  
S. Flint
Keyword(s):  
Biofilm Formation ◽  
Magnesium Ion ◽  
Content Type ◽  
High Sodium ◽  
Ion Concentrations ◽  
Sodium Calcium ◽  
Viable Cells ◽  
Anoxybacillus Flavithermus ◽  
Calcium And Magnesium ◽  
The Difference

ABSTRACTThis study investigated the effects of varied sodium, calcium, and magnesium concentrations in specialty milk formulations on biofilm formation byGeobacillusspp. andAnoxybacillus flavithermus. The numbers of attached viable cells (log CFU per square centimeter) after 6 to 18 h of biofilm formation by three dairy-derived strains ofGeobacillusand three dairy-derived strains ofA. flavithermuswere compared in two commercial milk formulations. Milk formulation B had relatively high sodium and low calcium and magnesium concentrations compared with those of milk formulation A, but the two formulations had comparable fat, protein, and lactose concentrations. Biofilm formation by the threeGeobacillusisolates was up to 4 log CFU cm−2lower in milk formulation B than in milk formulation A after 6 to 18 h, and the difference was often significant (P≤ 0.05). However, no significant differences (P≤ 0.05) were found when biofilm formations by the threeA. flavithermusisolates were compared in milk formulations A and B. Supplementation of milk formulation A with 100 mM NaCl significantly decreased (P≤ 0.05)Geobacillusbiofilm formation after 6 to 10 h. Furthermore, supplementation of milk formulation B with 2 mM CaCl2or 2 mM MgCl2significantly increased (P≤ 0.05)Geobacillusbiofilm formation after 10 to 18 h. It was concluded that relatively high free Na+and low free Ca2+and Mg2+concentrations in milk formulations are collectively required to inhibit biofilm formation byGeobacillusspp., whereas biofilm formation byA. flavithermusis not impacted by typical cation concentration differences of milk formulations.

Blood Changes in Calcium and Magnesium Ion Concentrations after Whole-Body X-Irradiation

1970 ◽  
Vol 42 (3) ◽  
pp. 560 ◽  
Author(s):  
L. Ababei ◽  
C. Haler ◽  
M. Trandafirescu ◽  
D. Cernătescu ◽  
M. Ionescu ◽  
...  
Keyword(s):  
Whole Body ◽  
Magnesium Ion ◽  
Ion Concentrations ◽  
X Irradiation ◽  
Calcium And Magnesium

scholarly journals ACTION OF MITOCHONDRIAL DNAASE I IN DESTROYING THE CAPACITY OF ISOLATED CELL NUCLEI TO FORM GELS

1957 ◽  
Vol 3 (5) ◽  
pp. 649-662 ◽  
Author(s):  
Alexander L. Dounce ◽  
Marguerite P. O'Connell ◽  
Kenneth J. Monty ◽  
Keyword(s):  
Rat Liver ◽  
Enzyme System ◽  
Sodium Dodecyl ◽  
Detergent Solution ◽  
Cell Nuclei ◽  
Ph Values ◽  
Residual Protein ◽  
Mitochondria Dna ◽  
Liver Nuclei ◽  
Isolated Cell

1. DNA prepared from non-gelable rat liver nuclei isolated in the presence of disrupted mitochondria at pH 6.0, has been compared with DNA obtained from gelable nuclei isolated at pH 4.0. The DNA of the non-gelable nuclei is partially depolymerized relative to the DNA of the gelable nuclei. 2. It has been found that sufficiently small quantities of crystallized DNAase I can cleave a very large part of the DNA of gelable nuclei isolated at pH 4 from the residual protein of these nuclei without causing extensive depolymerization of the DNA. At the same time the gelable nuclei are rendered non-gelable. 3. Partially purified DNAase II can also render gelable nuclei isolated at pH 4 non-gelable, and in so doing presumably also cleaves the DNA from the residual protein of the nuclei. 4. Mitochondrial DNAase I appears to be the enzyme responsible to a large extent for the cleavage of DNA from the residual protein of gelable rat liver cell nuclei with concomitant destruction of the gel-forming capability of these nuclei, when the nuclei are subjected to the action of disrupted mitochondria at pH 6.0 during the isolation procedure. 5. Mitochondrial DNAase II does not appear to exert appreciable action on nuclei during the course of isolation of the nuclei at pH 6.0 in the presence of disrupted mitochondria. 6. It is probable that DNAase I is not the sole enzyme responsible for destroying the gelability of nuclei isolated at pH 6.0 in the presence of disrupted mitochondria. Protease may be involved. 7. Sodium dodecyl sulfate at pH 6.0–6.3 cleaves the DNA of isolated gelable nuclei from the residual protein of these nuclei over a period of 2 to 3 hours. At pH 7.0–7.5, however, there is negligible cleavage over a period of 96 hours. 8. If non-gelable nuclei are isolated at pH 6.0 in the presence of disrupted mitochondria, DNA subsequently can be removed from them by the use of detergent at pH values ranging from 6.0–7.5 without the necessity of incubation in the detergent solution, since the DNA had already been detached from the residual protein by the action of the mitochondrial enzyme system during isolation of the nuclei.

scholarly journals DENSITY GRADIENT ISOLATION OF RAT LIVER NUCLEI WITH HIGH DNA CONTENT

1963 ◽  
Vol 17 (2) ◽  
pp. 231-236 ◽  
Author(s):  
Richard F. Fisher ◽  
David J. Holbrook ◽  
J. Logan Irvin
Keyword(s):  
Density Gradient ◽  
Rat Liver ◽  
Dna Content ◽  
Phosphorus Content ◽  
Sucrose Solution ◽  
Normal Liver ◽  
Sucrose Density Gradient ◽  
Pellet Fraction ◽  
Rat Liver Nuclei ◽  
Liver Nuclei

Rat liver nuclei, after preliminary isolation in 2.2 molar sucrose solution, were separated into density classes by centrifugation at 95,000 g for 45 to 85 minutes in a sucrose density gradient (density range, 1.28 to 1.33). Nuclei from normal liver separated into three bands with average DNA phosphorus content per nucleus of 0.67, 0.84, and 0.93 picogram for top, middle, and bottom bands, respectively. Nuclei from regenerating liver (26 hours after one-third hepatectomy) yielded three bands and a pellet fraction with average DNA phosphorus content per nucleus of 0.76, 1.02, 1.38, and 1.51 picograms (top to bottom of tube). This method appears capable of yielding nuclei which have increased their DNA content prior to mitosis, and this procedure should be valuable in studies of biochemical changes which occur in nuclei preparing for mitosis.

scholarly journals EFFECTS OF ALLOXAN AND REDUCED FOOD INTAKE ON LIVER DEOXYRIBOSE NUCLEIC ACID OF THE RAT

1959 ◽  
Vol 7 (2) ◽  
pp. 83-85 ◽  
Author(s):  
HENRY S. DI STEFANO ◽  
HAROLD F. DIERMEIER
Keyword(s):  
Nucleic Acid ◽  
Food Intake ◽  
Rat Liver ◽  
Liver Damage ◽  
Dna Content ◽  
Diabetic Rats ◽  
Deoxyribose Nucleic Acid ◽  
Liver Nuclei ◽  
Dna 2 ◽  
Complete Starvation

Effects of alloxan, reduced food intake, starvation and biopsy procedure on the deoxyribose nucleic acid (DNA) content of rat liver tetraploid nuclei have been investigated. It was found that: (1) Alloxan treatment resulted in an increased amount of DNA. (2) Reduced food intake of treated animals Played no part in this increase. (3) Complete starvation for a period of six days did not effect the amount of DNA in these nuclei. (4) An increased amount of DNA was found in tetraploid nuclei of rat liver 13 days after removal of a small biopsy sample. The increased DNA in tetraploid liver nuclei of alloxan diabetic rats may be explained on the basis of regeneration of liver tissue due to some submicroscopic liver damage caused by the drug.

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