A Study on induction of minicell formation by FtsZ overproducing L-form E. coli

Yılmaz, İsmail Cem
L-form organisms (or L-phase, L-variants) are cell wall-deficient (CWD) bacteria consisting of protoplasts and spheroplasts that have the ability to grow and divide. The mutant strain LW1655F+ (also known as L-form E. coli) was originally derived from the parental E. coli K-12 parental strain and is known to be deficient in cell wall, periplasmic space, flagella, fimbriae and outer membrane. Minicells are small cell-like structures that do not have genomic DNA and are produced during the logarithmic phase of growth during which division event does not occur. Minicell production in E. coli K-12 parental strain can be induced by introducing a mutation at the minB locus of the bacterial genome. Moreover, previous studies have shown that overproducing FtsZ to two to seven folds led to minicell production in rod-shaped E. coli K-12. The present study originally intended to investigate whether spherical; cell-wall deficient L-form E. coli is also capable of producing minicells upon overproduction of FtsZ. To achieve this, two types of model organisms were used: a) L-form E. coli, b) L-form E. coli overproducing 2.25-fold more FtsZ as constructed in the present study. Electron microscopy analyses of the organism demonstrated that L-form E. coli cells spontaneously produced vesicle-like structures. Such spontaneous vesicle production was previously reported for other L-form bacteria such as Listeria monocytogenes, yet the current study is the first to demonstrate this event in L-form E. coli. Furthermore, flow cytometric analyses revealed that overproduction of FtsZ in L-form E. coli significantly increased the number of vesicles released into the growth medium when compared to L-form E. coli. Although minicell formation by both L-form E. coli and its FtsZ overproducing derivative could not be verified and remained ambiguous, the present study demonstrated two new findings: (i) L-form E. coli spontaneously produces vesicle-like structures without any modification, and (ii) FtsZ overproduction in such cells leads to a significantly increased vesicle secretion.


A comparative study of monoaxial and coaxial PCL/gelatin/Poloxamer 188 scaffolds for bone tissue engineering
Alissa Alam, Hani; Dalgıç, Ali Deniz; Tezcaner, Ayşen; Özen, Can; Keskin, Dilek (2020-04-01)
Structure of fibrous scaffolds varies depending on the electrospinning method and parameters which will define cell fate. In this study, monoaxial and coaxial electrospun PCL/gelatin/P-188 scaffolds were characterized in terms of morphology, chemistry, mechanical property, water retention, weight loss, porosity and release properties. Coaxial fibers supported duel release of model hydrophilic protein (Beta-lactoglobulin) and hydrophobic agent vitamin K2. Novel PCL/P-188(Shell):Gelatin/P-188(Core) coaxial sc...
Evaluating Oxygen Tensions Related to Bone Marrow and Matrix for MSC Differentiation in 2D and 3D Biomimetic Lamellar Scaffolds
Sayin, Esen; Baran, Erkan Turker; Elsheikh, Ahmed; Mudera, Vivek; Cheema, Umber; Hasırcı, Vasıf Nejat (2021-04-01)
The physiological O-2 microenvironment of mesenchymal stem cells (MSCs) and osteoblasts and the dimensionality of a substrate are known to be important in regulating cell phenotype and function. By providing the physiologically normoxic environments of bone marrow (5%) and matrix (12%), we assessed their potential to maintain stemness, induce osteogenic differentiation, and enhance the material properties in the micropatterned collagen/silk fibroin scaffolds that were produced in 2D or 3D. Expression of ost...
YURDUGÜL, SEYHUN; Pancevska, Natalija-Atanasova; YILDIZ, GÜLGEZ GÖKÇE; Bozoglu, Faruk (2012-01-01)
The digestive system of the ruminants possesses anaerobic fungi, which are responsible for the degradation of cellulose and cell wall structures by their enzyme systems. An enzyme complex, bearing cellulase activity from Neocallimastix spp. which belongs to anaerobic rumen fungi, was partially isolated and its effect at various concentrations on bread quality was tested. The addition of enzyme complex into bread dough resulted in a decrease of hardness, gumminess and chewiness, providing a softer crumb, ind...
Conjugative transfer of antibiotic resistance genes from salmonella enterica serovar infantis to escherichia coli
Cesur, Aylin; Soyer, Yeşim; Department of Food Engineering (2018)
The usage and misusage of antibiotics in poultry, food-producing animals and human diseases have led to transmission of conjugative plasmids carrying antibiotic resistance genes from one microorganism to another, especially to the pathogenic bacteria. Multi-drug resistant Salmonella enterica serovar Infantis, an emerging serotype in poultry, has been spreading all around the world in a decade. Moreover, commensal microorganisms such as commensal Escherichia coli in the gut microbiota, functioning as a reser...
In Vivo detection of GPCR dimerizations in saccharomyces cerevisiae using FRET and BIFC
Üstünkaya, Beren; Son, Çağdaş Devrim; Department of Biology (2014)
G protein-coupled receptors (GPCRs) are a class of membrane proteins that are composed of seven transmembrane domain and mediate physiological response to a diverse array of stimuli. In eukaryotic microorganisms, GPCRs regulate cell growth, development, morphogenesis, motility, and life span. In higher eukaryotic organisms as humans, they mediate the action of hundreds of peptide hormones, sensory stimuli, odorants, neurotransmitters, and chemokine. Due to their wide spectrum of action mechanisms, GPCRs are...
Citation Formats
İ. C. Yılmaz, “A Study on induction of minicell formation by FtsZ overproducing L-form E. coli,” M.S. - Master of Science, Middle East Technical University, 2014.