Increase yield

这是一篇关于Increase yield的思维导图，主要内容有point mutation、Microbial strain improvement。

Increase yield

• point mutation
  • 100-1000 folds increase on yield
    • enhance gene expression
    • gene amplification
  • not change genotype
    • other wise you have a new compount
  • treat with mutagenic agents until the strain is produced
    • mutagens
      • base analogs
        • point
      • alkylating agents
        • point
      • Frame shift mutagens
        • addition
        • deletion
      • Subtopic
    • radiations
      • Ionizing
        • double strands breaks
      • Nonionizing
        • thymine dimmer
  • handle mutants
    • selection
      • e.x. antibiotic resistance
      • mutant gain a advantage than the parent strains
    • screening
      • e.x. auxotroph/prototroph
        • Subtopic
      • e.x. ames test
        • rate of back mutations in auxotroph strains
        • evaluate mutagenicity
      • mutant lose a function to grow in complete medium
• Microbial strain improvement
  • Transformation methods
  • Engineering principles
    • structural genes
      • enzymes for the product synthesis pathway/ the product(protein)'s gene
    • regulatory genes
      • onset and expression of the structural genes
        • precursors
        • cofactors
    • resistance genes
      • determine the risistence of the producer to this product
    • permeability genes
      • entry, exclusion, excretion of the product
  • Recombination
    • : physical exchange of genes between genetic
      • elements.
  • DNA shulffling
    • protoplast fusion in bacteria
      • can be same or different species
    • you don't have to know anything about the gene, you can combine on the phenotype level