Similarity Lederle

The Lederle group has used the AP similarity method to compare chemicals in their data base. have used the AP method in selecting... 

Soon after the introduction of chloramphenicol into medicine a second antibiotic with a broad antibacterial spectrum was discovered in the Lederle Laboratories . This substance was produced by Streptomyces aureofaciens and was named aureomycin. Later, a similar substance, terramycin, was isolated at Chas. Pfizer Inc. from the culture fluid of Streptcrmyces rimosus . The complete structure of terramycin was elucidated in 1953 and that of aureomycin a year later. 

Nilakantan et al. at Lederle Laboratories have described a similarity measure that is closely related to the Bemis-Kuntz measure, in that it is based... 

The efiectiveness of the BNB and NBN measures was assessed by simulated property-prediction experiments. These experiments involved the QSAR data sets studied previously by Pepperrell and Willetti" for the evaluation of distance-based similarity measures and a large set of 6-deoxyhexopyranose carbohydrates, which had previously been classified into 14 shape classes using numerical clustering methods based on torsional dissimilarity coefficients. The comparison encompassed the Bemis-Kuntz and Lederle measures, including not just the atom-triplet but also the atom-pair and atom-quadruplet versions of the former measure. The results were equivocal, in that it was impossible to... 

The concept of molecular similarity calculation within chemical information systems was pioneered at Sheffield University and first introduced into operational systems at Pfizer Central Research (UK) " and Lederle . It is now well-established within chemical information systems, both commercially available and developed in-house, as described in other papers in this volume. It is a powerful concept, which may be applied to both 2-D and 3-D structural representations, and to chemical reaction information, and used to support similarity searching and browsing, and file clustering and partitioning. 

In general, temperatures between 20 and 30 are most favorable for polymyxin and circulin production. The amount of polymyxin D produced by B, polymyxa strain Lederle B71 is independent of temperature in this range, but at 37 the yield of antibiotic is reduced to less than 10% (Stansly et al., 1948). Similarly, B. polymyxa strain Pfizer 2459 produces only 5 to 10% as much polymyxin B at 37 than at 30 . This may be related to the fact that at 30 , but not at 37 , reneutralization of the culture fluid occurs at the end of active growth (Paulus and Brenner, unpublished). 

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