الفهرس 
Inter-simple sequence repeat (ISSR)Only 14 pages are availabe for public view
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Abstract
Corynebacterium glutamicum is a small, non-motile Grampositive
commensal bacterium. It has a rod-shaped morphology with
swelled ends similar to a club. It does not form spores. The L-glutamate
producing microorganism C. glutamicum has an important role in the
amino acid fermentation industry. In the last few years, many genetic
engineering tools and worldwide analysis methods for this bacterium have
been established and successfully used, giving a detailed understanding of
its physiology and allowing the progress of effective producing strains.
L Tryptophan is considered as neutral amino acid. It is combined
in proteins during the procedure of mRNA translation. L Tryptophan is
one of the 9 essential amino acids of human which cannot be synthesized
internally by him, and need to be given with nutrition. Microbial
production is the main method for obtaining tryptophan for commercial
use. Typical microorganisms used for tryptophan production are E. coli
and C. glutamicum. Tryptophan producing strains of these bacteria have
been built by the classical mutagenic procedure or recombinant DNA
technology.
Mutation is the everlasting modification of the genome of an
organism, it occurs due to faults during DNA replication or due to
additional types of injury to DNA. Mutagens could be physical, chemical
or biological in origin. They may act directly on the DNA, causing direct
injury to the DNA, and mainly lead to replication error.
Start codon targeted polymorphism (SCoT), is a simple gene
targeted DNA marker depend on the short-conserved region in genes.
Primers for SCoT marker study were planned from the conserved region
surrounding the translation initiation codon ATG.
Inter-simple sequence repeats (ISSRs) are sites in the genome
lined by microsatellite sequences. PCR amplification of these regions by
using a single primer produce multiple amplification products that could.be used as a dominant multi locus marker system in knowing the genetic
variation in different organisms.
Increasing the production of tryptophan from C. glutamicum i.e
genetic improvement was the main target of the study. So, induction of
mutation using UV radiation was performed to achieve this goal. The
estimation of the produced tryptophan was done by biological assay using
E. coli auxotroph for tryptophan.
In this work, the final tryptophan yields were 29.4 μg/ml (50%
increment), 48.8 μg/ml (138.3% increment), 278.4 μg/ml (1259.4%
increment) and 81.6 μg/ml (295% increment) from strains 3, 6, 8 and 10
respectively. The tryptophan yield is remarkably increased especially in
strain 8 (298.5 μg/ml), then strain 10 (81.6 μg/ml). Molecular genetics
markers used (SCoT and ISSR) showed an ability to differentiate between
the two original strains and their mutants by the presence and absence of
certain DNA fragment bands, and that showed the genetic change that
took place after mutation that lead to increment of tryptophan production
by this method..