A kinetic study on the plasmid stability of three Lactococcus lactis strains

Avsaroglu, M. Dilek
Buzrul, Sencer
Sanlibaba, Pinar
Alpas, Hami
Akcelik, Mustafa
The plasmid stability of three wild type Lactococcus lactis strains and their mutants was investigated at different incubation time and temperatures in two different media [M17 broth and reconstituted skim milk (RSM)]. The results showed that both incubation times and temperature are effective on plasmid loss. The plasmid profiles of wild type strains exhibited 8 to 9 distinct plasmid species with molecular weights from 2.1 to 24.0 kb. Lactose fermentation ability was found to be encoded by 22.2 (strain U70), 23.6 (strain U29) and 24.0 (strain U52) kb plasmids in the wild type strains, respectively. The stabilities of the plasmids were explained by applying a second-order polynomial modeling system. Reasonable fittings were obtained for the model and the adjusted regression coefficients (R-adj(2)) were between 0.76 and 0.99 for the overall data. Overall, it was found that incubation time had the most profound effect on plasmid stability, with plasmid loss occurring after 72 h, while temperatures in the range of 15-40 degrees C also induced plasmid instability.


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Kaya, Hande; Çalık, Pınar; Department of Chemical Engineering (2006)
In this study, the benzaldehyde lyase (BAL, EC production in E. coli BL21 (DE3) pLySs as intracellular and in Bacillus species as extracellular were investigated, and comparison of the production capacity of the enzyme in the developed recombinant microorganisms were compared. For this purpose, firstly, PCR amplified bal gene was cloned into pRSETA vector which is under the control of strong T7 promoter and expressed in E. coli BL21 (DE3) pLysS strain. With developed recombinant E. coli BL21 (DE3)...
Influence of controlled-pH and uncontrolled-pH operations on recombinant benzaldehyde lyase production by Escherichia coli
Çalık, Pınar; Demir, AS (Elsevier BV, 2006-03-02)
To select the host microorganism having the highest benzaldehyde lyase (BAL) production capacity, pUC 18::bal gene was transferred into four Escherichia coli strains. As the highest enzyme activity was obtained with E. coli K12 (ATCC 10798) carrying pUC18::bal gene, BAL production medium was designed for K 12. Using the designed medium containing 8.0 kg m(-3) glucose, 5.0 kg m(-3) (NH4)(2)HPO4 and the salt solution, the effects of uncontrolled-pH and controlled-pH operations were investigated at uncontrolle...
Purification, characterization, and identification of a novel bifunctional catalase-phenol oxidase from Scytalidium thermophilum
Kocabas, Didem Sutay; Bakir, Ufuk; Phillips, Simon E. V.; McPherson, Michael J.; Ögel, Zümrüt Begüm (Springer Science and Business Media LLC, 2008-06-01)
A novel bifunctional catalase with an additional phenol oxidase activity was isolated from a thermophilic fungus, Scytalidium thermophilum. This extracellular enzyme was purified ca. 10-fold with 46% yield and was biochemically characterized. The enzyme contains heme and has a molecular weight of 320 kDa with four 80 kDa subunits and an isoelectric point of 5.0. Catalase and phenol oxidase activities were most stable at pH 7.0. The activation energies of catalase and phenol oxidase activities of the enzyme ...
Development of PCR methods for detection and quantification of genetically modified maize
Jabbari Farhoud, Houman; Gültekin, Güzin Candan; Department of Biotechnology (2010)
This study describes development of methods for screening, identification and quantification of genetic modifications in maize samples. Totally 88 maize samples were collected randomly throughout Turkey in three years from 2006 to 2008 and were analyzed. Two maize samples that were detected as GM positive in previous studies were selected as positive controls. Following the DNA extraction by manual CTAB method, conventional PCR methods were employed for screening of genetic modifications in samples by detec...
Killer toxin of Pichia anomala NCYC 432; purification, characterization and its exo-beta-1,3-glucanase activity
Izgu, Fatih; Altinbay, Demet; Acun, Tolga (Elsevier BV, 2006-08-02)
Pichia anomala NCYC 432 secretes a killer toxin which is inhibitory to a variety of yeasts including pathogenic Candida spp. The killer toxin in the culture supernatant was concentrated by ultratiltration and purified to homogenity by two successive gel filtration chromatographies with a TSK G2000SW column. Biochemical characterization of the toxin showed that it is a glycosylated protein with a molecular mass of 47 kDa and pI values of 3.4 and 3.7. The toxin showed high stability at pH values between 3 and...
Citation Formats
M. D. Avsaroglu, S. Buzrul, P. Sanlibaba, H. Alpas, and M. Akcelik, “A kinetic study on the plasmid stability of three Lactococcus lactis strains,” JOURNAL OF INDUSTRIAL MICROBIOLOGY & BIOTECHNOLOGY, pp. 729–737, 2007, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/39856.