Hybrid plasmid(s) contg. genes for nitrogen fixation - to introduce nitrogen fixing ability into yeast cells for prodn. of foodstuffs

摘要

Hybrid plasmids contg. (a) a DNA fragment of a yeast 2 micrometre plasmid, (b) a DNA segment contg. a yeast gene, (c) a bacterial plasmid DNA fragment, and (d) a DNA fragment contg. the genes responsible for fixing nitrogen, are new. Pref. the DNA fragment (a) is a fragment of the restriction between the Eco R1(1) and the Hind III (3) sites, as defined by Guerineau in Viruses and Plasmids in Fungi, Marcel Dekker, N.Y. 1979, ed. by P.A. Lemke. The yeast gene (b) is pref. URA3+ gene, the DNA fragments being adjacent to form a 'DNA yeast block.' The DNA fragment (c) pref. carries a lambda or lambdoid phage cos site to facilitate cloning, such as pHc 79 described by Collins, Methods in Enzymology, 68, 309, 1979. The DNA fragment carrying nitrogen-fixing genes is pref. derived from Klebsiella pneumoniae. Also claimed are cells and microorganisms contg. the hybrid plasmids. The plasmids may be used to introduce nitrogen-fixing genes into eucaryotic cells, esp. yeasts, their culture enabling foodstuffs to be produced without using nitrogenous fertilisers.