Cloning with ring

Natter S. Seiberler S, Hufnagl P, Binder BR, Hirschl AM. Ring J, Abeck D. Schmidt T, Valent P, Valenta R Isolation of cDNA clones coding for IgE autoantigens with serum IgE from atopic dermatitis patients. FASEB J 1998 12 1559-1569. 

Figure 26.3 Schematic representation of the steps involved in generating clonal isolates of transformed cells. Cells that are not transformed will terminally differentiate and die, while clonal growths of transformed cells will continue to proliferate and expand on the dish. Individual clones are isolated using cloning rings (glass cylinders that are 1 cm in diameter). Clones can also be pooled if it is desirable to have a population of transformed cells with a mixed origin (See also color insert).

Colonies of transformants are most effectively isolated enzymatically with cloning rings. Cloning rings are sterile glass cylinders 1 cm in diameter. 

Benzodiazepine derivates, seven-membered rings with 2 N atoms in 1,4 position are the pivotal structures of the benzodiazepine class of breakthrough CNS (central nervous system) drugs such as Librium and Valium. The most recent drug in this class, Sepracor s Lunesta (eszopiclone), is composed almost entirely of A-heterocyclics. Like most modern drugs, esczopi-clone also has a chiral center ... 

Isopenicillin N synthase (IPNS, Table 1) or ACV cyclase (Fig. 1) catalyzes the oxidative cyclization of ACV by the removal of four hydrogens from the tripeptide with the consumption of one molecule of oxygen [22], The newly formed C—N and C—S bonds of the respective p-lactam and thiazolidine rings are putatively made in a stepwise manner while the intermediates are enzyme bound [22]. IPNS from C. acremonium was purified [23a,23b] and its N-terminal sequence reported [24] in the early 1980s. Samson et al. [25] utilized the sequence data to clone the IPNS gene pcbC [5], IPNS has been extensively characterized with respect to its enzymology [23,26,27], substrate specificity, and catalytic mechanism [28-30],... 

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