Product screen

Analysis in diverse lines can facilitate identification of useful alleles that control expression of enzymes upstream of the carotenoid pathway, a feature that would not be evident from conventional end-product screening of breeding lines. Moreover, this characterization sets the stage for marker-assisted selection of superior endogenous alleles and facilitates selection of introduced transgenes that may be necessary to supplement the genotypic contribution required for a particular plant chemical outcome. 

Schmidt, M.A., Microfabricated chemical systems for product screening and synthesis, in Hoyle, W. (Ed.), Automated Synthetic Methods for Specialty Chemicals, pp. 14-24, Royal Society of Chemistry, Cambridge (2000). 

M. A., Microfabricated chemical systems for product screening and synthesis, in... 

Examples of successful natural product screens directed against proven targets include screens designed to look for inhibitors of bacterial cell wall biosynthesis. These screens were established once it became clear... 

FIGURE 2 Examples of the variety of structures obtained in natural product screens. I, zaragozic acid A, is an inhibitor of mammalian and fungal sterol synthesis, obtained from fungi (48) II, L-696,474, is an inhibitor of the HIV protease, obtained from fungi (51) III, dehydrosoyasaponin I, is an agonist of the calcium-activated potassium channel, obtained from a medicinal plant (58) IV, tetrandrine, is an inhibitor of L-type calcium channels, obtained from a plant (78). 

Natural product screening may capture a compound, such as an antibiotic, insecticide, or HMG-CoA reductase inhibitor, designed for the... 

Lombardi, V.R.M., Garcia, M., Rey, L., Cacabelos, R. (1999) Characterization of cytokine production, screening of lymphocyte subset patterns and in vitro apoptosis in healthy and Alzheimer s disease individuals. J. NeuroimmunoL, 97, 163-171. 

Figure 6.9 Retest results of the prima hit clones from CIAA stability (13-2H to 19-10A) and productivity screening (1-4Ato 10-4C). Comparable amounts of DERA cell-free...

Traditional approaches for natural product screening in drug discovery involve the testing of crude extracts obtained from microbial fermentation broths, plants, or marine organisms. When activity above a certain level is detected, active components are isolated and purified for identification. This process is often time consuming where the physicochemical characteristics of the active components are determined, known compounds are identified (dereplication), and the novel compounds are scaled-up for more detailed investigation. 

Shorter discovery timelines and accelerated development expectations have hindered the traditional approaches for natural products research. Furthermore, emphasis on chemical diversity presents a great challenge in this area, particularly because traditional natural products screening programs focus on one source of chemical diversity such as microorganisms or plants. Still, the primary issue remains how to assay this ideal source of new, biologically active compounds within the current timeframe necessary for modern drug discovery research. At the heart of this issue is the fact that traditional isolation and scale-up procedures are inefficient and often become the bottleneck in natural products dereplication. 

In summary, for a startup site that prefers to work on Macintosh platforms, BIOSTAR would be a good first choice. Conversely, for a Windows environment, CSAP would be an excellent starting package. For larger, cross-platform sites with heavier data management needs, and for those that already use other MDL products, SCREEN should be seriously considered. 

MAP and DAP fertilizers are made in a granulation process from ammonia and wet-process phosphoric acid. The acid is partially neutralized in a tank reactor. Ammoniation and granulation are completed in a rotary drum. Drying, cooling and product screening complete the process238. 

A disc circuit requires a smaller product screen. 

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