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.
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N.S. Rao and T.M. Shakila are and S.N. Bagchi was with the Department of Biological Sciences, R.D. University, Jabalpur-482 001, Madhya Pradesh, India. S.N. Bagchi is now with the Department of Microbiology, MDS University, Amjer-305 001, Rajasthan, India.
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Rao, N.S., Shakila, T.M. & Bagchi, S.N. De-regulated assimilation and over-production of amino acids in analogue-resistant mutants of a cyanobacterium, Phormidium uncinatum . World Journal of Microbiology & Biotechnology 11, 665–668 (1995). https://doi.org/10.1007/BF00361013
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DOI: https://doi.org/10.1007/BF00361013