Assays rapid screening

It should be pointed out that when using ethidium bromide the sensitivity of the assays varies depending on the physical state of the nucleic acids (see Table I). Ethidium does not discriminate between RNA and DNA, although dyes are available which bind DNA exclusively, so the relative amounts of each may be determined by taking two sets of measurements. Alternatively, nucleases (DNA-ase or RNA-ase) can be used to exclusively remove one or the other in a mixture. Nucleic acids from different sources (see Table II) also show a variation in sensitivity, and the fluorescence assay lacks the selectivity of the hybridization technique. Nevertheless, for rapid screening or quality-control applications the fluorescence assay is still the method of choice. 

Roelofs WL (1984) Electroanntenogram assays rapid and convenient screening procedures for pheromones. In Hummel HE, Millar TA (eds) Techniques in pheromone research. Springer, Berlin Heidelberg New York, pp 131-159... 

Besides these toxic effects, many studies showed the potential for oestrogenic activity of several sunscreen agents. These effects can be detected in vivo or at in vitro assays. The last are usually more sensitive than the former, concluding sometimes in an overestimation of the effects. Nevertheless, in vitro assays are faster and cheaper and allow a rapid screening of oestrogenic compounds. Therefore, a combination of different assays is recommended in order to have a wide spectrum of toxicity data that would allow performing a reliable risk assessment. 

Estimated from poster data presented in Rapid screening of aqueous solubility by a nephelometric assay ,... 

Probably the most sensitive biosensor for rapid screening has been the ORIGIN electrochemiluminescence system (IGEN, Gaithersburg, MD). The primary reason for the ORIGIN S enhanced sensitivity is that it preconcentrates the target prior to the assay. Immunomagnetic beads are... 

Combinatorial chemistry was developed in the early 1990s with pharmaceutical industry being the main driver [3], The rapid screening of potential drug molecules against well-defined assays had quickly become one of the major tools for the identification of novel lead candidates. 

LC/MS/MS with selected reaction monitoring (SRM) offers a fast and simple means to analyze biological matrices, which is a key factor in high-throughput CYP inhibition screens using liver microsomes. Potentially, the LC/MS/MS technique is suitable for analyses of cocktail substrates in other in vitro drug metabolism evaluations such as CYP induction/activation assays, rapid analysis of pooled liver microsomes, rapid reaction phenotyping of tissue (hepatic and extrahepatic) samples, as well as evaluation of hepatocytes/tissue slice CYP activity. ° ... 

Most of the analytical methods for the analysis of pesticides in food are based on instrumental approaches based on chromatography coupled to mass spectrometry. However, a great effort of development has been paid to develop rapid screening methods based on biological methods, such as, enzyme linked immunosorbent assays (ELISA). 

Unfortunately, none of these catalysts displayed practical levels of selectivity in the KR of aryl aUcyl yec-alcohols. Miller therefore embarked in the design of a third generation catalyst that could enable the KR of a larger number of substrates. In this context, he developed an elegant fluorescence-based activity assay which allowed rapid screening of a large number of structurally unique catalysts. This protocol based on proton-activated fluorescence led to the identification of octapeptide 52 as a highly selective catalyst for the KR of aryl alkyl. yec-alcohols but also alkyl yec-alcohols... 

A competitive inhibition screen is often the first step in understanding the DDI potential of a NCE. The definitive assessment of inhibition is the inhibition constant (K ), which provides not only the inhibition potency but also information on the mechanism of inhibition (competitive, non-competitive). However in the hit to lead profiling environment this approach is over-complex for the question being asked, and generates far too many samples to enable rapid screening of compound series. DDI assays based upon the IC50 principle are therefore favored. The relationship between K and IC50 for a competitive inhibitor is ... 

Evrard D, Touitou E, Kolusheva S, Fishov Y, Jelinek R. A new colorimetric assay for studying and rapid screening of membrane penetration enhancers. Pharm Res 2001 18 943-949. 

Kolusheva S, Boyer L, Jelinek R. A colorimetric assay for rapid screening of antimicrobial peptides. Nat Biotechnol 2000 18 225-227. 

Based on the observation that ellipticine binds preferentially to the RNAiDNA hybrid poly rArpoly dT, an assay was developed to rapidly screen large numbers of potential lead compounds for this property <2001JA6742>. The 3D structures of the compounds that preferentially bind to the RNAiDNA hybrid (ellipticine, ethidium, coralyne. 

Lai CC, Tsai CH, Tsai FJ, Wu JY, Lin WD, Lee CC (2002) Rapid screening assay of congenital adrenal hyperplasia by measuring 17 alpha-hydroxyprogesterone with high-performance liquid chromatography/electrospray ionization tandem mass spectrometry from dried blood spots. J Clin Lab Anal 16 20-25... 

An ELISA (enzyme-linked immunosorbent assay) allows for rapid screening and quantification of the presence of an antigen in a sample (Fig. 5-28b). Proteins in a sample are adsorbed to an inert surface, usually a 96-well polystyrene plate. The surface is washed with a solution of an inexpensive nonspecific protein (often casein from nonfat dry milk powder) to block proteins introduced in subsequent steps from also adsorbing to these surfaces. The surface is then treated with a solution containing the primary antibody—an antibody against the protein of interest. Unbound antibody is washed away and the surface is treated with a solution containing antibodies against the primary antibody. These secondary antibodies have been linked to an enzyme that catalyzes a reaction that forms a colored product. After unbound secondary antibody is washed away, the substrate of the antibody-linked enzyme is added. Product formation (monitored as color intensity) is proportional to the concentration of the protein of interest in the sample. 

Bedard, D. L., Unterman, R. D., Bopp, L. H., Brennan, M. J., Haberl, M. L. Johnson, C. (1986). Rapid assay for screening and characterizing microorganisms for the ability to degrade polychlorinated biphenyls. Applied and Environmental Microbiology, 51,761-8. 

In 1991, we first introduced the one-bead one-compound (OBOC ) combinatorial library method.1 Since then, it has been successfully applied to the identification of ligands for a large number of biological targets.2,3 Using well-established on-bead binding or functional assays, the OBOC method is highly efficient and practical. A random library of millions of beads can be rapidly screened in parallel for a specific acceptor molecule (receptor, antibody, enzyme, virus, etc.). The amount of acceptor needed is minute compared to solution phase assay in microtiter plates. The positive beads with active compounds are easily isolated and subjected to structural determination. For peptides that contain natural amino acids and have a free N-terminus, we routinely use an automatic protein sequencer with Edman chemistry, which converts each a-amino acid sequentially to its phenylthiohydantoin (PTH) derivatives, to determine the structure of peptide on the positive beads. 

J.M. Luk, U. Kongmuang, R.S.W. Tsang and A.A. Lindberg, An enzyme-linked immunoadsorbent assay to detect PCR products of the rfbS gene from serogroup D salmonellae a rapid screening prototype, J. Clin. Microbiol., 35 (1997) 714-718. 

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