Detection of Phosphatidylserine Externalization During Apoptosis. Shailaja Kasibhatla et al. An early event in apoptosis is the externalization of phosphatidylserine (PS), a phospholipid normally restricted to the inner leaflet of the plasma membrane. This apoptotic event can be monitored using Annexin V, a PS-specific binding protein. This protocol uses Annexin V-FITC as a probe, but Annexin V-biotin is also available, and binding can be revealed using streptavidin-FITC or oth - [Read Detection Of Phosphatidylserine Externalization During Apoptosis (Subscription Required)]
FM 4-64 is a lipophilic styryl dye and a vital stain: it fluoresces only in living cells, so cells cannot be fixed then stained nor stained then fixed. You must stain and observe living cells. FM 4-64 does not permeate cell membranes but, instead, intercalates into the plasma membrane is then
taken into the cells by endocytosis. - [Read FM 4-64 Labeling of Yeast Vacuole Membranes Protocol]
Accumulation of lipophilic substances in the plasma membrane may affect the membrane lipid order and consequently affect the function of these proteins. Changes in the activity of the Na+/K+ -ATPase, which is the major active transport system responsible for the electrochemical potential in mammalian cells, can therefore be an indication of the effect that a chemical may have on the viability of the cell membrane and possibly the whole cell. - [Read Hamster Ovary Cell NA+/K+ -ATPase Test]
During incubation period and the course of disease, SARS virus replicates and releases from cells. The level of virus varies greatly from sample to sample. At early stage of incubation period or during the late convalescent phase, the concentration of virus is very low in all kinds of samples. Virus is also detected at extremely low concentrations in plasma during... - [Read Kit for Rapid Enrichment of SARS Virus]
Protocol describes a method for isolation and stimulation of lymphocytes. Leukocyte-rich plasma is collected from whole blood and then centrifuged through Ficoll-Hypaque. The collected cells are resuspended in growth medium containing various mitogens to stimulate growth. - [Read Lymphocyte Isolation and Culture Protocol]
For cells grown in tissue culture, the most useful method of lysis is treating with detergents, as described in this protocol. Non-ionic detergents, such as NP-40, solubilize the plasma and intracellular membranes, break many weak intermolecular bonds, and solubilize most of the commonly studied protein antigens. RIPA lysis buffer may be used as a more rigorous extraction buffer to release all but the insoluble proteins of the cell and to break most weak noncovalent interactions. - [Read Lysing Tissue-Culture Cells for Immunoprecipitation Protocol]
Polyclonal antibodies can be isolated from animal plasma or serum using the procedure described in this protocol. The Gradiflow BF400 instrument has two liquid streams that circulate through a separation cartridge positioned between two electrodes and composed of three hydrogel polyacrylamide membranes, which define the channels for the two sample streams. The central membrane forms a physical barrier between the two streams. - [Read Preparation of Polyclonal Antibodies from Plasma or Serum Using the Gradiflow BF400]
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]
Protocol for the isolation of the lipid-rich microdomains of the plasma membrane, notably caveolae and lipid rafts. Methods for the isolation of lipid rafts are based on the insolubility of these structures in the nonionic detergent TritonX-100. Either the intact cells are treated with a detergent-containing solution or a post-nuclear supernatant is prepared from a cell homogenate and then Triton X-100 is added to this supernatant. - [Read S20 Purification of detergent-insoluble lipid rafts from cells and tissues.]
Protocol for steroid radioimmunoassay. Includes: SOLVENT DISTILLATION; PREPARATION OF PLASMA SAMPLES; EXTRACTION OF STEROIDS AND COLUMN PACKING; COLUMN CHROMATOGRAPHY; RADIOIMMUNOASSAY; SEPARATION OF BOUND AND FREE COUNTS; DIRECT ASSAYS; SHORT COLUMN CHROMATOGRAPHY. - [Read Steroid Radioimmunoassay 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)]
The cytotoxic effect of test chemicals in V79 cell culture can be determined by assessing damage to the plasma membrane as determined by a nucleic acid leakage assay. - [Read V79 Cytotoxicity Test for Membrane Damage]
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]
Accumulation of lipophilic substances, many of which may be environmental chemicals, affects the membrane lipid order and consequently affects the functions of these proteins. Since, the function of important cellular proteins, such as the H+-ATPase strongly depends upon the integrity of the lipid bilayer, the activity of the H+-ATPase may be used as a sensitive indicator of the effect that a chemical may have on the viability of the cell. - [Read Yeast Plasma Membrane H+ -ATPASE Toxicity Test]