Assignment of biological functions to specific plasmids in a local isolate of Rhizobium cicer

Yıldız, Eda
Özcengiz, Gülay
İçgen, Bülent
Alaeddınoglu, Ng
The genetic basis of symbiosis, mucoid structure and melanin biosynthesis in a local isolate of Rhizobium cicer was investigated. The strain was avery effective symbiont and produced substantial amounts of exopolysaccharides and melanin. It harbored three high-molar-mass plasmids of 55, 80 and 130 kb, respectively. Thirty-one melanin production-negative (Mep(-)) derivatives were obtained through plasmid curing. The plasmid patterns of cured derivatives indicated that the loss of 55 and/or 80 kb plasmids was sufficient for obtaining Mep- phenotype. The specific involvement of 55-kb plasmid in melanin production was confirmed upon re-introduction of this plasmid into one of the Mep- derivatives. Further investigation also indicated that the 130-kb plasmid might be necessary for both mucoidal appearance and symbiotic functions.


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Bayram, Sinan; Dengiz, Çağatay; GERÇEK, Yusuf Can; ÇETİN, İdil; TOPÇUL, Mehmet Rıfkı (Springer Science and Business Media LLC, 2020-01-01)
In this study, the structure of the purified extracellular eumelanin pigment isolated from Streptomyces spp. was elucidated by detailed analysis via two different spectroscopic techniques (FT-IR and NMR). In vitro antiproliferative effects of eumelanin were evaluated on HeLa cell line. These experiments were carried out with the evaluation of the parameters including cell viability, cell index, and mitotic index. With the cell viability and cell index, IC50 concentration of eumelanin was determined as 10 μM...
Cloning, characterization and heterologous expression of the aspartokinase and aspartate semialdehyde dehydrogenase genes of cephamycin C-producer Streptomyces clavuligerus
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Carbon flow through the lysine branch of the aspartate biosynthetic pathway is a rate-limiting step in the formation of cephamycin C, a broad spectrum P-lactam antibiotic produced by Streptomyces clavuligerus. In this study, genes which encode the enzymes catalyzing the first two steps of the aspartate pathway, ask (aspartokinase) and asd (aspartate semialdehyde dehydrogenase), in S. clavuligerus NRRL 3585 were cloned and sequenced. Nucleotide sequencing and codon preference analysis revealed three complete...
Targeted disruption of homoserine dehydrogenase gene in Streptomyces clavuligerus and its effects on cephamycin C production
Çaydaşı (Koca), Ayşe; Özcengiz, Gülay; Department of Biology (2006)
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 ...
ALTAY, G; BOZOGLU, F; RAY, B (Elsevier BV, 1994-08-01)
Sucrose-fermenting ability and nisin-producing traits were transferred to Lactococcus lactis strains by direct plate conjugation. (DPC), solid surface conjugation (SSC) and membrane filter conjugation. (MFC) with frequencies ranging from 2.6 x 10(-6) to 8.9 x 10(-10) transconjugant/donor colony forming unit (cfu). Plasmid pGK12 was transferred into plasmid-free Pediococcus acidilactici F3 by electroporation with a transfer frequency of 49 transformants/mu g DNA used.
Analysis of a bac operon-silenced strain suggests pleiotropic effects of bacilysin in Bacillus subtilis
Ertekin, Ozan; Taskin, Ash Aras; Demir, Mustafa; Karataş, Ayten; Özcengiz, Gülay (Springer Science and Business Media LLC, 2020-04-01)
Bacilysin, as the simplest peptide antibiotic made up of only L-alanine and L-anticapsin, is produced and excreted by Bacillus subtilis under the control of quorum sensing. We analyzed bacilysin-nonproducing strain OGU1 which was obtained by bacA-targeted pMutin T3 insertion into the parental strain genome resulting in a genomic organization (bacA '::lacZ::erm::bacABCDEF) to form an IPTG-inducible bac operon. Although IPTG induction provided 3- to 5-fold increment in the transcription of bac operon genes, n...
Citation Formats
E. Yıldız, G. Özcengiz, B. İçgen, and N. Alaeddınoglu, “Assignment of biological functions to specific plasmids in a local isolate of Rhizobium cicer,” FOLIA MICROBIOLOGICA, pp. 55–58, 1999, Accessed: 00, 2020. [Online]. Available: