Person: SARIYAR AKBULUT, BERNA
Loading...
Email Address
Birth Date
Research Projects
Organizational Units
Job Title
Last Name
SARIYAR AKBULUT
First Name
BERNA
Name
4 results
Search Results
Now showing 1 - 4 of 4
Publication Metadata only Potentiating the activity of berberine for Staphylococcus aureus in a combinatorial treatment with thymol(ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 2020) SARIYAR AKBULUT, BERNA; Aksoy, Cemile Selin; Avci, Fatma Gizem; Ugurel, Osman Mutluhan; Atas, Basak; Sayar, Nihat Alpagu; Akbulut, Berna SariyarA plethora of natural products emerges as attractive molecules in the struggle against antibiotic resistance. These molecules impose their bioactivities not only alone but also in combinations as well, which further enhances their effects. Berberine is a well-known isoquinoline alkaloid with antibacterial activity. Unfortunately, it is readily extruded, which significantly reduces its efficacy and restricts its potential. Thymol is a monoterpenic phenol that exhibits different biological activities but its major effect is observed only at relatively high concentrations, which raises concern on cytotoxicity. The aim of the study was to potentiate the antibacterial activity of berberine, in a combination treatment with thymol in the opportunistic pathogen Staphylococcus aureus and understand the antibacterial mechanism of the combination treatment. The synergism of berberine and thymol was first established by the checkerboard assay. Then the antibacterial mechanism of the synergistic combination was explored by growth curves, biofilm formation assay, SEM observation, and RNA-Seq based transcriptomic profiling. Checkerboard assay showed that 32 mu g mL(-1) berberine and 64 mu g mL(-1) thymol was a synergistic combination, both concentrations below their cytotoxicity limits for many cells. 32 mu g mL(-1) berberine and 32 mu g mL(-1) thymol was sufficient to inhibit biofilm formation. SEM images confirmed the morphological changes on the structure of combination treated cells. The major finding of the combination treatment from the transcriptomic analysis was the repression in the expression of virulence factors or genes related to virulence factors. Apart from the particular changes related to the cell envelope, the majority of expressional changes seemed to be similar to berberine-treated cells or to be resulting from general stress conditions. The findings of this work showed that when thymol was used in combination with berberine, it enhanced the antibacterial activity of berberine in a synergistic manner. Furthermore, thymol could be considered as an antivirulence agent, disarming S. aureus cells.Publication Metadata only Proteomics Evidence for the Activity of the Putative Antibacterial Plant Alkaloid (-)-Roemerine: Mainstreaming Omics-Guided Drug Discovery(MARY ANN LIEBERT, INC, 2015) SARIYAR AKBULUT, BERNA; Gokgoz, Nilay Budeyri; Akbulut, Berna SariyarDiscovery of new antibacterials with novel mechanisms is important to counteract the ingenious resistance mechanisms of bacteria. In this connection, omics-guided drug discovery offers a rigorous method in the quest of new antibacterials. (-)-Roemerine is a plant alkaloid that has been reported to possess putative antibacterial activity against Escherichia coli, Bacillus subtilis, and Salmonella typhimurium. The aim of the present study was to characterize the activity of (-)-roemerine in Escherichia coli TB1 using proteomics tools. With (-)-roemerine treatment, we found limited permeability through the outer membrane and repression of transport proteins involved in carbohydrate metabolism, resulting in poor carbon source availability. The shortfall of intracellular carbon sources in turn led to impaired cell growth. The reduction in the abundance of proteins related to translational machinery, amino acid biosynthesis, and metabolism was accompanied by a nutrient-limited state. The latter finding could suggest a metabolic shutdown in E. coli cells. High osmolarity was clearly not one of the reasons of bacterial death by (-)-roemerine. These observations collectively attest to the promise of plant omics and profiling of putative drug candidates using proteomics tools. Omics-guided drug discovery deserves greater attention in mainstream pharmacology so as to better understand the plants' medicinal potentials.Publication Metadata only Proteomic response of Escherichia coli to the alkaloid extract of Papaver polychaetum(SPRINGER, 2010) SARIYAR AKBULUT, BERNA; Ozbalci, Cagakan; Unsal, Caglayan; Kazan, Dilek; Sariyar-Akbulut, BernaThe cellular response of Escherichia coli exposed to alkaloids extracted from a biennial endemic plant, Papaver polychaetum, was explored using proteome analysis. Following determination of the minimum inhibitory concentration of the berberine-containing plant extract as 1,250 mu g/mL, E. coli cells were grown in the presence of 750 mu g/mL extract. The response of the bacteria to the extract, with berberine found as the major alkaloid, was analyzed on two-dimensional gels. The differentially expressed proteins in the presence of 750 mu g/mL extract were identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry. These proteins included those that play vital roles for maintenance such as protein synthesis (elongation factor-Ts), transport (oligopeptide-binding protein A, uncharacterized amino-acid ABC transporter ATP binding protein YECC), energy metabolism (alpha-subunit of ATP synthase, pyridine nucleotide transhydrogenase STHA) and regulation. These results provide clues for understanding the mechanism of the alkaloid extract-induced stress and cytotoxicity on E. coli. The altered proteins can serve as potential targets for development of innovative therapeutic agents.Publication Metadata only Cellular distribution of activity for three enzymes with maltose binding protein as fusion partner and the structural implications(SCIENTIFIC TECHNICAL RESEARCH COUNCIL TURKEY-TUBITAK, 2010) SARIYAR AKBULUT, BERNA; Utkur, Ozde F.; Akbulut, Berna Sariyar; Hortacsu, AmableThe bacterial SEC pathway is commonly used for secretion of heterologous proteins in E. coli by fusing them to transported proteins to facilitate downstream processing. While some proteins are translocated very efficiently, some reside in the cytoplasm. In this work, maltose binding protein (MBP) was fused to 3 cytoplamic enzymes from Thermus thermophilus (serine protease, 251 residues; glucose isomerase, 381 residues; pullulanase, 718 residues) to study the protein transport from the cytoplasm by quantifying the distribution of activities in different cellular compartments. Pullulanase activity was harvested exclusively in the periplasm; however, glucose isomerase activity was harvested exclusively in the cytoplasm. Considerable serine protease activity was found in the periplasm, but after 10 h of induction activity dropped sharply and no activity was found thereafter in either compartment. This was attributed to the instability of the plasmid probably caused by the proteolytic activity of the protease Computations of hypothetical folding rates and secondary structure contents of the proteins showed that folding rates, in addition to alpha-helix and beta-sheet contents of proteins, could be important determinants for efficient translocation by the SEC pathway. These results may give clues to predict whether a protein would be a suitable fusion tail for periplasmic transport with MBP.