Cell centrifugation

Benzoylcholine is a substrate of pseudo-cholinesterase but not of the true cholinesterase. It inhibits the true cholinesterase of man (laked red cells centrifuged and the supernatant liquid diluted 1/150, acetylcholine substrate 0 005 m) from 30 per cent at a concentration of 0-1 M to 85 per cent at a concentration of 0-3 M. Benzoylcholine injected intravenously into rabbits will, at a dose of 8-14 mg./kg. body weight, produce a head drop lasting 40-120 sec. 

Resuspend the pellet in 5 ml phosphate-buffered saline, by vortexing gently. After a 60-s pause to allow residual ethanol to diffuse from the cells, centrifuge the sample (200 x g for 5 min). Discard the supernatant. 

Count the CLL cells, centrifuge at 200 for 5 min at room temperature (RT), and resuspend in fresh complete RPMI media at 2 x lO " cells/ml. 

McKnight et al. [28] Vertically oriented nanofibers-l-DNA Chinese hamster ovary (CHO) cells - centrifugation and compression Part of cells was lost, small production of GFP cytotoxic response was not observed... 

Although the conditions used for the measurement of both expressible moisture and water uptake ability are arbitrary, the two can be performed under similar conditions. One of the real benefits of the two tests, with arbitrarily defined working parameters, is that they can, in theory, be done in parallel, e.g., by placing four samples for expressible moisture and four samples for water uptake ability in the same eight-cell centrifuge. In this case, the differences observed reflect the differences between... 

A relatively simple and quick procedure for the isolation of Photosystem I-enriched particles from the thermophilic cyanobacterium Phormidium laminosum, without the use of detergents for solubilization, is described. The procedure involves sonication of cells, centrifugation and DEAE-cellulose chromatography. The particles had an 02 uptake activity of up to 200 pmol 02. mg chlorophyll h 1 and appeared as vesicles of 200 100 nm diameter when observed under electron microscopy. The analysis of the chlorophyll-protein complexes by polyacrylamide gel electrophoresis showed that these particles are enriched in the complexes associated with Photosystem I and partially depleted in those associated with Photosystem II. The particles did not contain ferredoxin and were active in NADP-photoreduction only in the presence of added ferredox in. They were also able to photoreduce externally added electron mediators using ascorbate as electron donor, the reduced mediators can be coupled to hydrogenase for the production of H2 or for the activation of cyanobacterial phosphoribulokinase using a ferredoxin/thioredoxin system. 

Combine the required amount of CsCl stock solution, 1 pg of undetermined DNA, 1 fig of Micrococcus luteus reference DNA (buoyant density 1.7311 g/ml),6 and bring to a final volume of 500 fi with distilled water. Load centrifuge cells. Centrifugation is generally for 20 hr at 44,000 rpm.17... 

Cultured cells were used for the Raman studies reported in Section 5.3.2. For this, the cells were grown directly onto carefully cleaned and sterilized CaF2 substrates, and then incubated for various times in a cell culture environment with the drug carrier systems reported below. Before spectroscopic data acquisition, the cells were formalin fixed and resuspended in buffer solution. Raman spectra of the exfoliated human cells were obtained from cells centrifuged (see Section 5.2.2) onto Cap2 windows. The preparation of the drug delivery systems (deuterated liposomes) has been reported elsewhere [13]. 

Perform a cell count by making a 1 10 dilution of the T-ceU suspension with serum-free media and then a 1 2 dilution with 0.4% stock concentration of trypan blue. Count the cells using a hemacytometer and detennine the total number of T cells. Centrifuge the cell suspension at 300g for 10 min at 4-8°C. 

Remove supernate the following day and feed (free cells centrifuged from the supernate can be resuspended and replanted). Keep at 37°C in CO2. 

Downstream processing Intracellular products have to be extracted from the cells (by sonication, freeze thawing, and/or homogenization), and separated from the cells (centrifugation or filtration). Extracellular products require concentration and separation from the bulk supernatant. 

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