Liquid Assay

TABLE 5. Comparison of Sensitivity of Standard Pol A Assay and the Salmonella Mutagenicity Assay  

TABLE 6. Agents That Have Been Reported to Be Preferentially Lethal for E, coli Pol A ( Killing Curves )  

Strain. By these criteria, methyl methanesulfonate, A -acetoxyfluorenylacet-amide, captan, and others are preferential inhibitors of the pol Ai strain (Tables 7 and 8). On the other hand, streptomycin and chloramphenicol, although they induce lethality in both indicator strains, do not preferentially kill the pol Ar strain (SI = 1.12 and 1.02, respectively). It should be noted that this procedure is compatible with metabolic activation. Thus, the precarcinogens 2-aminofluorene and cyclophosphamide, which require metabolic activation by hepatic enzymes, do not preferentially inhibit the pol Ai strain in the absence of rat liver microsomes, but do so in the presence of this preparation (Tables 7 and 8). This procedure has the added advantage that results obtained by this modified pol Ai assay are expressed quantitatively, rather than as differences in the diameters of the zones of growth inhibition. As will be seen below, this modified procedure greatly increases the usefulness of the pol A assay (Table 9). 

Some investigators(also T. G. Mitchell, personal communication) have reported a simplification of this liquid assay procedure in which the enumeration of viable cells is replaced by the determination of the turbidity of (undiluted) treated and control cultures. Although this modification is less expensive and more rapid—results are read immediately as opposed to the requirement for overnight incubation—we have some reservations about this modification, since it is known that DNA-inhibiting agents have a propensity for unbalanced growth, i.e., a continued synthesis of RNA and proteins in the absence of DNA synthesis, which is characterized by an increase in the 

TABLE 7. Preferential Inhibition of Pol A, Cells by DNA-Modifying Agents (Liquid Suspension)  

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Raw Material Feed (Typical of the analyses required for a liquid) Assay, wt per cent min ... 

Odell, W.D. Daughaday, W.H. Principles of Competitive Protein Binding Assays Lippincott Philadelphia 1971. Christian, G.D. Clinical chemistry. Analytical Chemistry John Wiley and Sons Inc. New York, 1994 611-628. Ullman, E.E., Langen, J., Clapp, J.J., Eds. Liquid Assay Analysis of International Development on Isotopic and Non-Isotopic Immunoassay Masson New York, 1981 113. Sharma, A. Schulman, S.G. Fluorescence analytical methods and their applications. Introduction to Fluorescence Spectroscopy, WHey-lntexsdeace.l ew York, 1999 123-158. 

Under these assumptions, conditions in the cold tower will remain unchanged. Equation (13.122) still relates the product liquid assay xp, natural feed liquid assay xp, and cold-tower gas effluent assay yp. With ric = IS, G/F = 2.03, xp/xp = 4.0, and = 2.32, yp/xp = 0.4558. 

Several of the assay principles can also be used in liquid assays making such assay set-ups possible where clones after propagation in small cultures can be screened in pools. Such systems can be automated for high throughput screening systems. 

Passive. . Active (colony hybridization). . (continuous cultivation) (agar-assay, liquid assay) ... 

Species DSM number Agar assay (dihydrouracil) Liquid assay (U/ml) (hydantoin)... 

Rinderknecht et al. (14) designed a liquid assay for measuring a-amylase activity using amylose that had been covalently linked to a dye, Remazol Brilliant Blue R (RBB). In principle, this dye can be coupled to every soluble polysaccharide. RBB was coupled to... 

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