Show/Hide Menu
Hide/Show Apps
Logout
Türkçe
Türkçe
Search
Search
Login
Login
OpenMETU
OpenMETU
About
About
Open Science Policy
Open Science Policy
Open Access Guideline
Open Access Guideline
Postgraduate Thesis Guideline
Postgraduate Thesis Guideline
Communities & Collections
Communities & Collections
Help
Help
Frequently Asked Questions
Frequently Asked Questions
Guides
Guides
Thesis submission
Thesis submission
MS without thesis term project submission
MS without thesis term project submission
Publication submission with DOI
Publication submission with DOI
Publication submission
Publication submission
Supporting Information
Supporting Information
General Information
General Information
Copyright, Embargo and License
Copyright, Embargo and License
Contact us
Contact us
Targeted disruption of homoserine dehydrogenase gene in Streptomyces clavuligerus and its effects on cephamycin C production
Download
index.pdf
Date
2006
Author
Çaydaşı (Koca), Ayşe
Metadata
Show full item record
Item Usage Stats
246
views
107
downloads
Cite This
The members of the genus Streptomyces are well-known for their capacity to synthesize a vast repertoire of secondary metabolites, including many useful antibiotics and proteins. Streptomyces clavuligerus is the producer of the medically important β-lactam antibiotics such as cephamycin C and the potent β-lactamase inhibitor clavulanic acid. The aspartate pathway of S. clavuligerus is an important primary metabolic pathway providing substrates for β-lactam synthesis. This pathway uses L-aspartic acid as the precursor for the biosynthesis of the amino acids L-lysine, L-methionine, L-isoleucine, L-threonine and several important metabolic intermediates. L-α-aminoadipic acid (α-AAA) required for β-lactam synthesis is a catabolic product of L-lysine produced from the lysine branch of the aspartate pathway. The carbon flow through the L-lysine-specific branch of aspartate pathway is limiting for the formation of cephamycin C. Formation of L-homoserine from aspartate semialdehyde (ASA) is the first step of the other branch of the aspartate pathway leading to L-threonine, L-isoleucine and L-methionine synthesis and is catalyzed by homoserine dehydrogenase (HSD, EC 1.1.1.3). Regulation of the activity or biosynthesis of the HSD of S. clavuligerus determines the availability of ASA for the biosynthesis of L-lysine and α-AAA. The gene encoding for homoserine dehydrogenase (hom) was previously cloned from S. clavuligerus NRRL 3585 and characterized in our laboratory. In this study, the hom gene was disrupted via insertion of a kanamycin resistance cassette into this gene which was subsequently transferred to S. clavuligerus cells using the Streptomyces plasmid vector pIJ486. A hom mutant of S. clavuligerus (AK39) was formed through integration into the chromosome by double crossing over and the effects of hom disruption on cephamycin C yields were investigated. Disruption of hom gene resulted in a 1.7 to 2.0 fold increase in specific cephamycin C production in chemically defined medium (CDM).
Subject Keywords
Microbiology.
URI
http://etd.lib.metu.edu.tr/upload/12607402/index.pdf
https://hdl.handle.net/11511/16354
Collections
Graduate School of Natural and Applied Sciences, Thesis
Suggestions
OpenMETU
Core
Proteome-wide analysis of the functional roles of Bacilysin biosynthesis in Bacillus subtilis
Taşkın Aras, Aslı; Özcengiz, Gülay; Department of Biology (2010)
The members of the genus Bacillus produce a wide variety of secondary metabolites with antimetabolic and pharmacological activities. Most of these metabolites are small peptides that have unusual components and chemical bonds and synthesized nonribosomally by multifunctional enzyme complexes called peptide synthetases. Bacilysin, being produced and excreted by certain strains of Bacillus subtilis, is one of the simplest peptide antibiotics known. It is a dipeptide with an N-terminal L-alanine and an unusual...
Investigation of cytocidal effect of K5 type yeast killer protein on sensitive microbial cells
Sertkaya, Abdullah; İzgü, Kadri Fatih; Department of Biology (2005)
Some yeasts secrete polypeptide toxins, which are lethal to other sensitive yeast cells, gram-positive pathogenic bacteria and pathogenic fungi. Therefore these are designated as killer toxins. Killer toxins are suggested as potent antimicrobial agents especially for the protection of fermentation process against contaminating yeasts, biological control of undesirable yeasts in the preservation of foods. Moreover they are promising antimicrobial agents in the medical field; due to immune system suppressing ...
Characterisation of local isolates of Enterobacteriaceae from Turkey
İçgen, Bülent; Gültekin, Güzin Candan; Özcengiz, Gülay (Elsevier BV, 2002-01-01)
20 local isolates of enterics belonging to the genera Salmonella, Enterobacter Proteus, Citrobacter from human, chicken and/or egg were characterised for their antibiotic resistance patterns, plasmid profiles, phage types, outer membrane proteins, and lipopolysaccharide patterns. Relatedness of these characteristics for epidemiological analysis was assessed. 18 (90%) strains were resistant to at least one antibiotic and those (multi-drug resistant ones) resisting to two or more antibiotics constituted 50% o...
Analysis of the genetic determinant for production of the pediocin P of Pediococcus pentosaecus Pep 1
Osmanagaoglu, O; Beyatli, Y; Gündüz, Ufuk; Sacilik, SC (2000-01-01)
Pediococcus pentosaceus Pep1 is a vacuum-packaged Turkish sausage isolate which produces a potentially novel bacteriocin of the pediocin (anti-Listeria) family of peptides designated as pediocin P. Curing experiments and plasmid profile analysis indicated that both bacteriocin immunity and production determinants were linked and encoded by 9.0 MDa plasmid, pHD1.0. Attempts to transform purified plasmid pHD1.0 into recipient Escherichia coli JM109 cells by electroporation were successful but none of the E. c...
High hydrostatic pressure induced inactivation kinetics of e. coli o157:h7 and s. aureus in carrot juice and analysis of cell volume change
Pilavtepe, Mutlu; Alpas, Hami; Department of Food Engineering (2007)
The main objective of this study was to determine the pressure induced inactivation mechanism of pressure-resistant Escherichia coli O157:H7 933 and Staphylococcus aureus 485 in a low acid food. Firstly, inactivation curves of pathogens were obtained at 200 to 400 MPa at 40ºC in peptone water and carrot juice. First-order and Weibull models were fitted and Weibull model described the inactivation curves of both pathogens more accurately than first-order model, revealing that food systems could exhibit eithe...
Citation Formats
IEEE
ACM
APA
CHICAGO
MLA
BibTeX
A. Çaydaşı (Koca), “Targeted disruption of homoserine dehydrogenase gene in Streptomyces clavuligerus and its effects on cephamycin C production,” M.S. - Master of Science, Middle East Technical University, 2006.