Molecular assays modeling

The antiviral activities of natural products, including ingredients, fractions and extracts, need to be evaluated by various anti-viral models, including in vitro and in vivo models. Besides, the analysis of assay results of natural products is also very important. In the present section, the models to evaluate the in vitro anti-viral activities of potential natural products have been summarized, and the evaluation methods of several representative models have been introduced. The antiviral models include molecular level models and cellular level models (Table 3.2 Chattopadhyay et al. 2009). 

Taxonomically close to the Annonaceae, the Lauraceae family abounds with apor-phinoid alkaloids. A remarkable advance in the search for topoisomerase inhibitors from Lauraceae has been provided by Woo et al. (6). Using DNA-unwinding assay and structural modeling, they showed that dicentrine can attain a relatively planar conformation and molecular bulk which allow it to occupy the active site of topoisomerase II which becomes inactive. The requirement of a suboptimal conformation to achieve DNA binding appears to make dicentrine less potent against topoisomerase II than the... 

Recently, SETA BioMedicals has developed a new near-infrared squaraine-based label Seta-633, which can be used to study the interaction between low-molecular-weight analytes and proteins using fluorescence lifetime as the readout parameter [19]. This label exhibits lower quantum yields and shorter fluorescence lifetimes when free in solution, but these values substantially increase upon interaction with proteins, which is contrary to tracers like Cy5 or Alexa 647. It was demonstrated in a model assay that a biotinylated Seta-633 binds to anti-biotin with high specificity. Importantly, the lifetime of Seta-633-biotin increases about 2.76 fold upon binding to a specific antibody (anti-biotin, MW =160 kDa), while the titration with BSA or nonspecific antibody does not result in a noticeable change in lifetime (Fig. 13). The label is compatible with readily available light sources (635 nm or 640 nm lasers) and filter sets (as for Cy5 or Alexa 647) and its... 

PAbs against 2,4,5-TCP have been prepared after theoretical and molecular modeling chemical studies [226]. Competitive direct and indirect ELIS As have been developed, but as before the latter format was shown to be more robust. The indirect immunoassay has an excellent LOD near 0.05 pg L . The selectivity of the assay is high in relation to other chlorophenols frequently present in real samples, but as with the 2,4,6-TCP assay the brominated analogs may also be recognized. The 2,4,5-TCP immunoassay is stable in media with pH... 

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