Cell fractionation of cellular components using Percoll a synthetic, colloidal solution of polyvinylpyrrolidone coated silica, specifically designed for sedimentation centrifugation. Percoll becomes a simple matter to establish a linear density gradient. Organelle separations are much easier to accomplish on Percoll density gradients than on sucrose gradients. - [Read Equilibrium Density Gradient Percoll Protocol]
The protocol described in this protocol has been used principally for analyzing the Golgi, endoplasmic reticulum and trans-Golgi network but markers for other compartments (e.g.
ERGIC and endosomes) have also been analyzed. Modifications either to the gradient density range or the centrifugation conditions influence the ability of the gradient to resolve multiple compartments. - [Read Fractionation of Golgi, ER, TGN and Other Membrane Compartments in Pre-Formed Iodixanol Gradients]
Generally in iodixanol gradients the density of organelles decreases in the series: peroxisomes, mitochondria, lysosomes, ER, Golgi, although in Dictyostelium discoideum, the lysosomes are denser than the mitochondria. Iodixanol gradients can usually provide satisfactory resolution of all these membrane particles although it may be necessary to modulate either the gradient or centrifugation parameters in order to optimize a particular separation. - [Read Fractionation of Mitochondria, Lysosomes, Peroxisomes, ER and Golgi in Pre-formed Iodixanol Gradient]
The protocol consists of a method for the generation of cytoplasmic extracts from mammalian cells (in this case, 293T cells) without the disruption of polyribosomes, the separation of ribosomal components and polyribosomes by sucrose gradient centrifugation, the isolation of mRNA from these fractions, and detection of mRNA by Northern blot analysis. - [Read Northern Blot Analysis of mRNA From Mammalian Polyribosomes Protocol]
The employment of differential centrifugation to prepare crude fractions of subcellular particles from homogenates is often a necessary first step to a subsequent purification of one or more particles on a density gradient. This protocol describes the use of differential centrifugation to fractionate a mammalian liver
homogenate but similar methods should be applicable to all mammalian tissues and cultured cells. - [Read Preparation of Crude Subcellular Fractions by Differential Centrifugation Protocol]
Laboratory sample cleanup is a necessary part for analytical preparation analysis. The removal of Contaminants such as proteins, cell debris and other materials is an important step. Typically this has been done by using Acetonitrile and then Centrifugation to pellet the debris leaving the clean supernant. After this process supernatant can be used for further analysis by HPLC, GC, MS and other analysis tandem methods. HTS Labs. - [Read Protein Precipitation Microplate]
A solution containing plasmid DNA, saturating amounts of ethidium bromide, and CsCl (44% w/v) is layered between two solutions of lesser (35% w/v CsCl) and greater density (59% w/v CsCl). During centrifugation to equilibrium, the closed circular plasmid DNA and linear DNAs form bands at different densities. - [Read Purification of Closed Circular DNA by Equilibrium Centrifugation in CsCl-Ethidium Bromide Gradient]
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]
This protocol describes a discontinuous gradient, which resolves the mitochondria from both lighter and denser organelles. Because the centrifugation is carried out for 4 h, diffusion will create a partially continuous gradient and this probably contributes to the resolution of the mitochondria from the lighter lysosomes. - [Read Purification of Mammalian Liver Mitochondria by Flotation Through a Pre-formed Discontinuous Iodixan]
Protocol describes the standard method to recover nucleic acids from aqueous solutions by precipitation of DNA with ethanol. Subnanogram amounts of DNA (and RNA) can be quantitatively precipitated with ethanol, collected by centrifugation, and redissolved within minutes. - [Read Standard Ethanol Precipitation of DNA in Microcentrifuge Tubes Protocol]
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)]
Plasma membranes are isolated from the yeast Saccharomyces cerevisiae. The cell wall is initially digested by helicase, followed by hypoosmotic lysis and homogenization. Membranes are prepared by subsequent differential centrifugation. The activity of the H+-ATPase is then determined by measuring the amount of inorganic phosphate released from ATP. - [Read Yeast Plasma Membrane H+ -ATPASE Toxcity Test Protocol]
A Single Stranded Plasmid DNA Isolation Protocol describing the production and isolation of single-stranded DNA (ssDNA) using bacteriophagemid-containing bacteria and helper phage. Infection of the host cells with helper phage allows for packaging of ssDNA into bacteriophage. The ssDNA can then be isolated from phage particles.
Tubulin is polymerized into microtubules by incubating tubulin at 37°C with GTP. A nucleation seed is added when the purpose is to assay microtubule elongation. Tubulin can also be polymerized for the purposes of recycling the tubulin or labeling the microtubules with fluorescently labeled tubulin. Based on the protocol by Timothy Mitchison of Harvard University.