These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: An autoselection system in recombinant Kluyveromyces lactis enhances cloned gene stability and provides freedom in medium selection.
    Author: Hsieh HP, Da Silva NA.
    Journal: Appl Microbiol Biotechnol; 1998 Feb; 49(2):147-52. PubMed ID: 9534254.
    Abstract:
    An autoselection system for increasing plasmid stability in Kluyveromyces lactis, based on the blockage of the pyrimidine de novo and salvage pathways, was investigated. In a manner analogous to that used in Saccharomyces cerevisiae, a putative "fur 1" mutation was selected in a uraA K. lactis strain using 5-fluorouracil and 5-fluorocytosine plates. Survival of the mutant required expression of a plasmid-borne URA3 gene regardless of the culture medium employed, verifying the efficacy of this autoselection system in K. lactis. The expression of heterologous invertase, encoded by the S. cerevisiae SUC2 gene, was studied during long-term sequential batch cultures (70 generations) in complex yeast/peptone/glucose medium. The fur 1 mutant successfully retained the plasmid; invertase specific activity remained above 90% of the initial level. Furthermore, no mutation reversion was observed. In contrast, for the control non-fur 1 strain, only 4% of the cells retained the plasmid after 70 generations, and invertase specific activity dropped to less than 10% of the initial level. Experiments comparing growth and activity in different media indicated the potential for improving productivity through medium enrichment using this autoselection system.
    [Abstract] [Full Text] [Related] [New Search]