title: De-regulated assimilation and over-production of amino acids in analogue-resistant mutants of a cyanobacterium, Phormidium uncinatum.
abstract: Mutant strains of Phormidium uncinatum resistant to fluoro-phenylalanine, aztryptophan, fluorotyrosine and azaleucine accumulated a wide range of amino acids, notably glutamic acid, lysine, tyrosine and phenylalanine, and exhibited de-regulated valine and phenylalanine transport. While acetohydroxy acid synthase in azaleucine-resistant mutants lost valine- and leucine-sensitivity, 3-deoxy-DXXX-arabinoheplulosonate-7-phosphate (DAHP) synthase and prephenate dehydratase in aromatic analogue-resistant strains became phenylalanine-insensitive and shikimate and prephenate dehydrogenases were activated by tyrosine. In addition, activities of nitrate-assimilating enzymes were higher in the mutants, which also exhibited increased nitrogen, protein and phycocyanin contents. The proteins in the mutants were better digested upon enzymatic-treatments and feeding trials than those of the wild type, indicating that they are usable as single-cell protein.
authors.affiliation: , .
authors.forename: N S
authors.initials: NS
authors.lastname: Rao
authors.forename: T M
authors.initials: TM
authors.lastname: Shakila
authors.forename: S N
authors.initials: SN
authors.lastname: Bagchi