density Protocols

Category: Nucleic Acid Purification Protocols: DNA Isolation Protocols: DNA Plasmid Preps Protocols

Solutions containing plasmid DNA are adjusted to a density of 1.55 g/ml with solid CsCl.  The intercalating dye, ethidium bromide, which binds differentially to closed circular and linear DNAs, is then added to a concentration of 200 mu;g/ml.  During centrifugation to equilibrium, the closed circular DNA and linear DNAs form bands at different densities. - [Read Purification of Closed Circular DNA by Equilibrium Centrifugation in CsCl-Ethidium Bromide Gradients]

Category: Cell Organelle Protocols: Subcellular Fractionation Protocols: Membrane Isolation Protocols

This protocol uses a "light mitochondrial" pellet from a mammalian liver homogenate. The gradient thus has to resolve a variety of denser components (peroxisomes, lysosomes, mitochondria) from the Golgi membranes, which have a low density in iodixanol (1.06-1.09 g/ml) [1]. The protocol is specifically tailored to the purification of Golgi membranes from this pellet and is unsuitable for the isolation or analysis of other organelles present in the light mitochondrial fraction. - [Read Purification of Golgi Membranes from a Light Mitochondrial Fraction in a Self-Generated Gradient]

Category: Cell Biology and Cell Culture

The separation depends on the use of a hyperosmotic density barrier to separate the two types of leukocyte. - [Read Purification of leukocyte fractions from rat peritoneal exudates by density barrier sedimentation.]

Category: Cell Organelle Protocols: Subcellular Fractionation Protocols: Mitochondria Isolation Protocols

A procedure developed to purify simultaneously peroxisomes and mitochondria from spinach (Spirnacia olercea L.) leaf under isoosmotic and low viscosity conditions. This method involves differential centrifugation and density gradient centrifugation on four layers of Percoll. - [Read Purification of Peroxisomes and Mitochondria from Spinach Leaf by Percoll Gradient Centrifugation]

Category: Cell Organelle Protocols: Subcellular Fractionation Protocols: Peroxisome Isolation Protocols

A procedure developed to purify simultaneously peroxisomes and mitochondria from spinach (Spirnacia olercea L.) leaf under isoosmotic and low viscosity conditions. This method involves differential centrifugation and density gradient centrifugation on four layers of Percoll. - [Read Purification of Peroxisomes and Mitochondria from Spinach Leaf by Percoll Gradient Centrifugation]

Category: Cell Organelle Protocols: Subcellular Fractionation Protocols: Peroxisome Isolation Protocols

Peroxisomes can be purified in iodixanol gradients in high yield (80-90%) with no detectable contamination from any other organelle. This is a property unique to iodixanol because the densities of other organelles, particularly that of mitochondria (approx ρ = 1.14 g/ml) and endoplasmic reticulum (approx ρ = 1.13 g/ml) are much lower than that of peroxisomes (approx ρ = 1.18 g/ml). - [Read Purification of Peroxisomes using a Density Barrier in a Swinging-Bucket Rotor]

Category: Cell Biology and Cell Culture

Protocol for the recovery of a highly viable fraction for use in fertilization. Protocol uses an iodinated density gradient medium to adjust the density of the raw ejaculate to approx 1.170 g/ml by mixing with a high density medium (ρ >1.26 g/ml) and loading it beneath a discontinuous gradient. - [Read Purification of viable bovine spermatozoa of normal morphology.]

Category: Yeast Protocols: Yeast Genetics Protocols: Yeast Replication Protocols

Protocol for replication timing by density transfer. - [Read Replication Timing by Density Transfer Protocol]

Category: DNA Protocols: Cosmid Library Protocols

Unamplified cosmid libraries are plated at high density onto 150-mm nitrocellulose or nylon filters and screened by hybridization - [Read Screening an Unamplified Cosmid Library by Hybridization: Plating the Library onto Filters Protocol]

Category: Cell Biology and Cell Culture

Method separates monocytes and lymphocytes on the basis of density and size. - [Read Separation of monocytes from human leukocyte-rich plasma by flotation.]

Category: General Research Protocols and Methods: Spectrophotometry Protocols

Spectrophotometric Measurement of Nucleic Acids' Concentration Tool. This bioinformatic program help calculate the concentration of nucleic acids according to optical density (including DNA, RNA, oligonucleotides). Zbio - [Read Spectrophotometric Measurement of Nucleic Acids' Concentration Tool]

Category: Cell Organelle Protocols: Subcellular Fractionation Protocols

In the routine method described in this protocol, chylomicron-free plasma is adjusted to 12% (w/v) iodixanol and the sample, essentially fills an approx 3 ml tube for a near-vertical rotor. During the centrifugation VLDL, LDL and HDL particles and also plasma proteins migrate from all parts of the sample to their final buoyant density banding position in the self-forming density gradient. - [Read Subfractionation of Low-Density Lipoprotein (LDL)]

Category: Epigenetics and Methylation Protocols: 5-Aza-dC Treatment AZA Procedure

"Cells were seeded at a density of 1X106 cells/100-mm dish with 10% FBS and allowed to attach over a 24-h period. 5-Aza-dC (Sigma) was then added to a final concentration of 0.2–1
M, and the cells were allowed to grow for 5 days. The medium with or w - [Read Treatment of Cells with 5-aza-dC. protocol PDF]

Category: Pharmacology and Toxicology Protocols: Cytotoxicity Protocols: Microorganism Cytotoxicity Assays Protocols

The proliferation rate of the yeast, Saccharomyces cerevisiae, may be regarded as an overall indicator of the physiological status of the cell.  Therefore, the effect of various toxic substances on different cell functions will be reflected by changes in the rate of proliferation.  It is possible to determine the toxicity of a test substance simply by measuring cell density. - [Read Yeast Growth Rate Cytotoxicity Test]