gradient Protocols

Category: Primary Cell Isolation and Culture Protocols: Laser Capture Microdissection Protocols

Protocol for 2-D polyacrylamide gel electrophoresis. Includes: 50 ml IEF Lysis Buffer; 10X Electrophoresis Running Buffer (10 L); 30% Acrylamide Stock (1 liter); Separating Acrylamide Gel; 50 ml Equilibration Buffer I; 50 ml Equilibration Buffer II; Transfer Buffer; Sample Preparation; Tissue Processing; Reswelling; Prepare Gradient Acrylamide Gel (9-18%); Transfer and Sequencing of Proteins. - [Read 2-D Polyacrylamide Gel Electrophoresis Protocol]

Category: Cell Organelle Protocols: Subcellular Fractionation Protocols

Protocol describes systems in which the membranes are allowed to float through a density gradient from a dense load zone. This is an ideal format. - [Read A Self-generated Gradient to Discriminate a Cytosolic or Membrane Location of Large Protein Complex]

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

OptiPrep Application sheet C14 describes procedures for determining the density and sedimenting properties of any cell (of any size or density) using either a continuous or discontinuous gradient of iodixanol. This Application Sheet describes procedures aimed at isolating specifically a relatively low-density cell fraction from any tissue. - [Read C25 Isolation from spleen, thymus, pancreas, alveolar tissue and other tissues]

Category: Cell Organelle Protocols: Nucleus Protocols

Cajal Body Isolation Protocol. Protocol includes: Sonication, Removal Nucleoi, Gradient One, Gradient two, Concentration and final enrichment of cajal bodies. Also includes: Making 2.55M sucrose stock and Analysis of the enriched Cajal body fraction. - [Read Cajal Body Isolation Protocol]

Category: Cell Biology and Cell Culture

Cell fractionation techniques are presented for the design of gradient systems for separating one or more cell types from lavages of body cavities or from mechanically or enzymically-dissociated tissues. Includes: Preparation of cell suspension for gradient loading; Fractionation by buoyant density; Fractionation on the basis of cell size. - [Read Cell Fractionation of a Mixed Population of Cells]

Category: Immunology: Chemotaxis

Chemotaxis Assay, Springer Lab. A chemotaxis assay's function is to assess whether a factor or molecule of interest has chemotactic activity on a motile cell type. Chemotaxis is the ability of a factor to cause the migration of a cell. The chemotactic assay is based on the creation of a chemical gradient of the chemotactic agent which will cause cells to migrate through the gradient towards the chemotactic agent. - [Read Chemotaxis Assay]

Category: Cell Biology and Cell Culture

This chemotaxis assay protocol is based on the premise of creating a gradient of the chemotactic agent and allowing cells to migrate through a membrane towards the chemotactic agent. A chemotaxis assay can determine whether your protein or small molecule of interest has chemotactic activity on a specific cell type. Chemotaxis is then the ability of a protein to direct the migration of a specific cell. - [Read Chemotaxis Assay Protocol]

Category: Cell Organelle Protocols: Nucleus Protocols

The key step is the lysis which solubilizes centrosomes away from nuclei by very low ionic strength lysis after treatment of cells with nocodazole and cytochalasin B. The released centrosomes are then centrifuged onto a Ficoll cushion (to avoid pelleting) and the interface between the lysate and the Ficoll is collected and the centrosomes are concentrated on a sucrose gradient. Fractions are assayed by spindown and double IF with 5051 serum and anti-tubulin and the pooled fractions are frozen... - [Read CHO Centrosome Prep Protocol]

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: 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: 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: Viral Protocols

Protocol for gradient purification of AT2 inactivated HIV-1. - [Read Gradient Purification of AT2 Inactivated HIV-1 Protocol]

Category: Fungi Protocols: Neurospora Protocols

Information and tips on how to prepare and use gradient plates. - [Read How to Prepare and Use Gradient Plates]

Category: Immunology: Mononuclear Cell Isolation Protocols

This protocol uses the PBMC fraction enriched in with monocytes by density gradient centrifugations (protocol may be found at www.methods.info). Reduction of the amount of microbeads in comparison to Miltenyi protocol reduces the costs of the experiment. - [Read Isolation of Monocytes from Enriched PBMCs using CD14 Magnetic Beads Protocol]

Category: Cell Biology and Cell Culture

This protocol uses the PBMC fraction enriched in with monocytes by density gradient centrifugations. Reduction of the amount of microbeads reduces the costs of the experiment. - [Read Isolation of monocytes from monocyte enriched PBMC fraction using CD14]

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

A discontinuous gradient of iodixanol is used in which the crude mitochondrial fraction is layered beneath the preformed gradient. In this protocol the osmolality of the gradient is approx 600 mOsm and the crude mitochondrial fraction is loaded in 40% iodixanol rather than 50% iodixanol. - [Read Isolation of Yeast Mitochondria in aPre-Formed Iodixanol Gradient]

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 Detection Protocols: Nucleic Acid Blotting Protocols

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]

Category: Cell Organelle Protocols: Subcellular Fractionation Protocols

Protocol for percoll gradient. Includes: Forming gradient, Removing percoll and reagents. - [Read Percoll Gradient Protocol]

Category: Cell Organelle Protocols: Subcellular Fractionation Protocols

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]

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

The first part of the isolation procedure is a flotation through a continuous iodixanol gradient; this gradient is essentially a resolving gradient in which the caveolin-rich vesicles are concentrated in the top third of the gradient, while the predominantly caveolin-poor vesicles band in denser regions. A second discontinuous gradient is essentially a concentration gradient to band the caveolin-rich vesicles sharply at an interface. - [Read Purification of Caveolae Membranes from a Plasma Membrane Fraction of Cultured Cells and Tissues]