A study on cobalt adaptation and memory retention of freshwater bacteria isolates

Çıtır, Gözde
The mucus-dwelling bacteria previously isolated from the surface of a freshwater fish species (Alburnus alburnus from Lake Mogan, Ankara), were studied to discover their cobalt resistance. The minimum inhibitory concentrations (MIC) were determined for a total of thirty six bacterial isolates. The results of the resistance studies led us to design experiments on adaptation to cobalt and subsequent memory retention. Three selected isolates were exposed to an inhibitory cobalt concentration as a mixed culture and individually. The delayed formation of colonies along with competitive exclusion of one of the isolates in the mixed culture were recorded. The delay for colony formation was followed up for liquid culture conditions. After some of our isolates acclimated to cobalt and started to exhibit constant time of growth period, it is assumed that they were adapted. We regarded adaptation as a result of memory formation. Next, we did a further study to find out how long this memory could be retained via serial multiple passages in cobalt free medium. We expressed our observations quantitatively by measuring the growth by using spectrophotometer and by performing viable counts. Interestingly, where there was a high CFU, the photometric values were very low. We interpreted the finding such that the presence of cobalt above tolerance limits were causing size reduction in the cells. So that their presence was underestimated by optic devices in visible range. Our study hinted that freshwater bacteria was adapting cobalt in a memory based mechanism and able to retain this memory for some time.


Biochemical and genetic characterization of halobacterium salinarium strain isolated from Tuz Lake in central Anatolia
Çakıcı, Özgür; Yücel, Ayşe Meral; Department of Biochemistry (2004)
In this study, a halophilic archaea Halobacterium salinarium TG13 which is isolated from Tuz Lake in Central Anatolia was characterized biochemically and genetically. Halobacterium salinarium DSM3754 and Halobacterium salinarium S9 strains were used as a reference strain through the experiments. In biochemical characterization; total protein profiles of strains was compared by using 1D SDS PAGE. Total protein profile of the isolated strain has shown differences. The SDS-PAGE profile of the purified purple m...
Multiple antibiotic resistance of surface mucus dwelling bacterial populations in freshwater fish
Özaktaş, Tuğba; Gözen, Ayşe Gül; Department of Biology (2007)
Surface mucus of a freshwater fish, Alburnus alburnus (bleak), caught from Lake Mogan, situated in south of Ankara, was collected in different seasons. The total cultivable bacteria were enumerated by spread plate method on nine different media. Bacteria were isolated based on colony morphologies and pigmentation. A total of sixty bacterial isolates obtained. The mucus-dwelling bacteria were first tested for resistance against ampicillin and kanamycin; then streptomycin and chloramphenicol were added to the...
Characterization and purification of a bacteriocin produced by Leuconostoc mesenteroides subsp. cremoris
Dündar, Halil; Bozoğlu, Faruk; Department of Biotechnology (2006)
In this study, a new bacteriocin isolated from a Leuconostoc mesenteroides subsp. cremoris strain was purified to homogeneity by pH mediated cell adsorption-desorption, solid phase extraction with Amberlite XAD-16, cation-exchange chromatography and hydrophobic interaction chromatography. The purification resulted in an electrophoretically pure protein that was smaller than 6 kDa as judged by SDS-PAGE. The bacteriocin was found to be very hydrophobic and cationic and could be adsorbed by synthetic calcium s...
A comparative assessment of the Black Sea anchovy stock using holistic production and analytical age structure models
Akkuş, Gizem; Gücü, Ali Cemal (2022-3-01)
The Black Sea anchovy (Engraulis encrasicolus) is economically and ecologically the most importantcommercial fish species in the Black Sea. Therefore, a management plan targeting the maximum sustainableyield has gained importance in recent years. The present study aims to provide a comprehensive assessment byusing only Turkish data to evaluate the status of the Black Sea anchovy stock and compare the differentapproaches outcomes. For this, ASPIC (1968-2014) as a holistic production model and XSA (2005-2014)...
A Survey of Niche Overlap and Adaptive Trait Responses of Turkish Honeybee Subspecies to Climate
Kükrer, Mert; Bilgin, Cemal Can; Turak, Ayşe (2016-11-05)
Introduction: Over 24 subspecies or “geographic races” of honeybees in the world appear to have diversified following isolation during the Pleistocene glaciations. Research on their differences in morphology, biogeography, behavior and genetics suggest that Turkish races belong mostly to the same lineage, but evolved in extremely different habitats. Foraging strategies, honey storage, production of young, overwintering success, swarming behavior or aggression show differences between races. Such traits migh...
Citation Formats
G. Çıtır, “A study on cobalt adaptation and memory retention of freshwater bacteria isolates,” M.S. - Master of Science, Middle East Technical University, 2010.