gradients Protocols

Category: Protein Protocols: Protein Trafficking

Protocol is based on methods for the resolution of GLUT4 containing vesicles and the identification of phosphoinositide kinase containing vesicles in 3T3-L1 adipocytes. They may have a wider application to any low-medium density membranes. Protocol incorporates the strategy of using a low density microsome fraction as the gradient input, commonly used in GLUT 4 studies that may have a wider application to other investigations. - [Read Analysis of Membrane Trafficking and Intracellular Signaling in Self-Generated Iodixanol Gradients]

Category: Cell Biology and Cell Culture

Techniques on how to create gradients of iodixanol for the fractionation of mammalian cells. These gradients can be generated as pre-formed discontinuous or continuous gradients. These gradients are invariably run in swinging-bucket rotors in low-speed centrifuges. - [Read C2 Preparation of pre-formed iodixanol gradients for mammalian cells.]

Category: Cell Biology and Cell Culture

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]

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

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]

Category: Cell Organelle Protocols: Subcellular Fractionation Protocols

A number of density gradient strategies have been developed for the fractionation of human erythrocytes according to their age. As the cells age, so their density tends to increase; reticulocytes therefore tend to have the lowest densities. Reticulocytes have frequently been partially purified on discontinuous gradients of arabinogalactan; the actual density range being quite varied, from quite broad ones. - [Read Fractionation of Human Erythrocytes (Normal or Sickle) and Reticulocytes in Discontinuous Iodixanol]

Category: Plant Biology Protocols: Plant Proteins, Peptides and Antigens

Protocol describes a method for performing isoelectric fractionation of a maize embryo sample using a multicompartment electrolyzer(MCE). This prefractionation of proteins having pIs within a certain pH interval is essential for allowing high loads of protein to be resolved on narrow and ultra-narrow immobilized pH gradients used in 2D electrophoresis. The isoelectric membranes in the MCE act like isoelectric traps capturing all the protein species having pIs encompassing the pI value of each... - [Read Fractionation of Maize Embryo Proteins for 2-D Gel Electrophoresis Using Multicompartment Electrolyz]

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

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]

Category: Cell Organelle Protocols: Subcellular Fractionation Protocols

Fractionation of (a) vacuolar and subvacuolar vesicles and (b) vacuole and cytoplasm-to-vacuole targeting (Cvt) vesicles from yeast spheroplasts in a pre-formed discontinuous iodixanol gradients. Protocol includes: Formation of yeast spheroplasts; Isolation and vesiculation of the vacuoles; Separation of the vacuolar and subvacuolar vesicles; Separation of vacuoles and Cvt vesicles from a yeast spheroplast lysate. - [Read Fractionation of Vacuolar and Subvacuolar vesicles and Vacuole and Cytoplasm-to-Vacuole Targeting]

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

This protocol is concerned with the use of iodixanol gradients in an analytical mode to study the membrane localization of a particular protein or function. Continuous gradients are best suited to this task. One of the protocols described in this protocol starts with a discontinuous gradient, but since the gradient is centrifuged at 174,000g for 16 h it will become continuous by diffusion. - [Read Fractionation of Yeast Membranes in Pre-Formed Continuous Iodixanol Gradients]

Category: Plant Biology Protocols: Arabidopsis Genetics Protocols

Protocol for the isolation of Arabidopsis nuclei and measurement of gene transcription rates using nuclear run-on assays. Plant materials are ground in hexylene glycol-based buffers and highly enriched nuclear fractions are obtained using Percoll density gradients. Standard and small-scale protocols are presented, along with a tested method for nuclear run-on assays. The entire process may be completed within 3 days. - [Read Isolation of Arabidopsis Nuclei and Measurement of Gene Transcription Rates Protocol]

Category: Cell Biology and Cell Culture

Purification protocols of the viruses: HIV-1, Lassa virus, oncornavirus and other retroviruses. Protocol uses an iodixanol gradient in a sedimentation velocity mode to purifyHIV-1 virions without affecting the infectivity of the virus. In rate-zonal iodixanol gradients the HIV-1 was effectively separated both from Vif and from the microvesicles. - [Read M5 Velocity (rate zonal) gradients for purification and assembly analysis of viruses.]

Category: Nucleic Acid Electrophoresis Protocols

Protocol for the preparation of electrolyte gradient gels. Electrolyte gradients are formed when buffers of different concentrations are used in the upper (low electrolyte concentration) and lower (high electrolyte concentration) chambers of the electrophoresis device. - [Read Preparation of Electrolyte Gradient Gels Protocol]

Category: Viral Protocols

Protocol is used to prepare the arms of any bacteriophage {lambda} vector. - [Read Purification of Bacteriophage lambda Arms: Centrifugation through Sucrose Density Gradients Protocol]

Category: Viral Protocols

Isopycnic centrifugation through CsCl gradients is used to prepare infectious bacteriophage {lambda} particles of the highest purity that are essentially free of contaminating bacterial nucleic acids. - [Read Purification of Bacteriophage lambda Particles by Isopycnic Centrifugation through CsCl Gradients]

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

Although Percoll gradients were able to provide a purified sporocyst fraction, because these particles do not all band in a discrete manner in such gradients, they were unable to provide a simultaneous isolation of a pure oocyst wall fraction. Gradients formed from this protocol on the other hand are able to provide purified sporocysts and oocyst walls in the same gradient. - [Read Purification of Oocyst Walls and Sporocysts from Toxoplasma gondii Protocol]

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

Peroxisomes can be purified in self-generated iodixanol gradients in high yield (80-90%) with no detectable contamination from any other organelle. In iodixanol peroxisomes are the densest of the major subcellular organelles (ρ = 1.18-1.20 g/ml) present in the light mitochondrial fraction from mammalian tissues and cells. - [Read Purification of Peroxisomes in a Self-Generated Gradient]

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: Viral Protocols

Protocol for the purification of recombinant adeno-associated virus (rAAV) and parvovirus in pre-formed iodixanol gradients. - [Read Purification of Recombinant Adeno-Associated Virus (rAAV) and Parovirus Protocol]

Category: Cell Biology and Cell Culture

Summary of the techniques used for the purification of viruses using pre-formed iodixanol gradients. Viruses purified include: Semliki Forest, Retrovirus (from human melanoma cells), Rabies, Polyoma, Papillomavirus, Lassa, Influenza, Bovine viral diarrhea. - [Read Summary of Methods using Pre-formed Iodixanol Gradients for the Purification of Virsues.]