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  1. Feb 2018
    1. On 2016 Feb 02, Martine Crasnier-Mednansky commented:

      More needs to be said to fully understand the implication of the pioneering work by Novick and Weiner Novick A, 1957. The first action of an inducer is to induce a specific permeability thereby allowing the inducer concentration inside the cells to reach a higher level than the one in the medium. Such concentration dictates to the cell the production of the necessary enzymes for catabolism, and is generally sufficient to insure the same production in the cell’s descendants. Novick and Weiner reported that, at low concentration of an artificial inducer (TMG), descendants of a bacterial cell which had not yet been induced were not induced which resulted in two populations of bacteria, i.e., 'fully induced' and 'not induced', the all-or-none 'enzyme induction phenomenon'. The culture maintains its previous state of induction (so to speak) because induced cells grow more slowly than non-induced cells. Therefore, a minimum concentration of inducer is insufficient to maintain a population of induced cells. Novick and Weiner then concluded: "Some differences which arise in a clone of organisms may be the result of changes in cellular systems other than the primary genetic endowment of the cell". Even though Novick and Weiner used a non-metabolized inducer, their work is of consequence to contemporary work.


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