Cell debris

Other iavestigations of cross-flow filtration iaclude the study of the coaceatratioa of bacteria (41), the coaceatratioa of fermentation cell debris (42), the coaceatratioa of electrocoatiag paiat (43), the chemical effects oa cross-flow filtratioa of primary sewage efflueat (44), and the use of tubes of different materials, dimensions, and porosity with several slurries (45). 

The way that the aldehyde requirement was discovered by Cormier and Strehler is extraordinary and noteworthy. First, they found that a boiled bacterial extract stimulated luminescence when it was added to a weakly luminescing NADH-activated bacterial extract. They thought that the stimulation was due to certain substances associated with the cell debris existing in the extract. Thus, they tested the extracts of various animal tissues in the hope of finding a substance that would... 

Yellow fevert Aqueous homogenate of chick embryos infected with attenuated yellow fever virus 170 1 Centrifugation to remove cell debris 2 Freeze drying Infectivity-titration in cell cultures by plaque assay Tests to exclude extraneous viruses... 

The initial processing steps are determined to a large extent by the location of the product species, and they generally consist of cell/broth separation and/or cell debris removal. For products retained within the biomass during production, it is first necessary to concentrate the cell suspension before homogenization or chemical treatment to release the product. Clarification to remove the suspended solids is the process goal at this stage. 

The hypothesis is supported by two additional observations (24). First, mean cell volume for P. brevis in the absence of aponin remained constant for 8 hours, but, in the presence of aponin, a notable increase was observed within an hour and continued for eight hours. Second, Trypan blue (Cl 23850) tests indicated increased cell permeability in the presence of aponin viable, motile cells were only slightly stained swollen cells and cell debris were highly stained. 

Fig. 6.2. Caco-2 epithelial cell monolayers cultured with T. spiralis L1 larvae in (A) the absence or (B) presence of 1 mg ml 1 rat monoclonal, tyvelose-specific antibody 9D4 (McVay etal., 2000). Monolayers were fixed and stained with trypan blue as described in ManWarren etal. (1997). (A) Serpentine trails of nuclei in dead cells are evident, revealing the paths travelled by larvae. (B) Tyvelose-specific antibody has inhibited the migration of the larva such that it is encumbered in cell debris and has pulled up a large area of the monolayer, creating a plaque (P). Bar = 50 urn. Photomicrograph prepared by C. McVay, TTUHSC, Lubbock, Texas. 

Transfer powder into a 50-ml Falcon-style tube, measure the volume of powder, and add an equal volume of lysis buffer to suspend cell proteins in buffer. Centrifuge at 3500 Xg (4000 rpm in a Sigma 4K15 centrifuge, rotor 11150) for 5 min at 4° to pellet the cell debris. 

Spin at 9500 rpm ( 8200y) for 5 min at 4° and transfer the supernatant into a new cold microfuge tube. This step removes most of the cell debris, leaving a cleared lysate. 

In a number of methods, isolation of the nucleoprotein complex (stage 2) is avoided. In the isolation of ribonucleic acid from beef pancreas,1241 nuclear material and cell debris are removed from a normal-saline extract of the minced tissue, which is then brought to half-saturation with sodium chloride (to dissociate the protein from the nucleic acid). After removal of the protein, the nucleic acid is precipitated with alcohol. However, the suggestion has been made126 that it is more satisfactory to isolate the nucleoprotein first, and this has been carried out, for instance, in the extraction of the ribonucleic acid from fowl sarcoma GRCH 15.126 Nucleoprotein complexes have also been isolated from baker s yeast127 and have been separated into various fractions, the nucleic acids from which differ slightly in composition. In addition, nucleoproteins have been isolated by complex formation with cetyltrimethylammonium bromide.128... 

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