Browsing by Author "Cebeci, Aysun"

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High Carbohydrate Diet Decreases Microbial Diversity and Increases Il-1β Levels in Mice Colon
(Korean Society Food Science & Technology-kosfost, 2024) Ulutas, Mehmet Sefa; Aydin, Erkin; Cebeci, Aysun
Western diet is known to contribute to intestinal dysbiosis and the progression of inflammation. Although the Turkish diet has different macronutrient contents, the intestinal inflammatory disease incidences in T & uuml;rkiye are comparable to Western countries. Thus, we hypothesized that high carbohydrate diets also contribute to inflammation of the colon. We compared diets with different macronutrient compositions and investigated their effects on colonic microbiota, cytokine, histology, and tight junction protein levels. High carbohydrate diet caused the lowest microbial diversity and is accompanied by the highest expression of interleukin-1 beta and claudin-1. A low carbohydrate diet with zero fiber resulted in the lowest inflammatory markers as well as the lowest occludin and claudin levels. Overall, our results indicate that carbohydrate and fiber contents of the diets are important contributors to colon health.
Citation - WoS: 35
Citation - Scopus: 36
Glucose-Dependent Anaplerosis in Cancer Cells Is Required for Cellular Redox Balance in the Absence of Glutamine
(Nature Portfolio, 2016) Cetinbas, Naniye Malli; Sudderth, Jessica; Harris, Robert C.; Cebeci, Aysun; Negri, Gian L.; Yilmaz, Oemer H.; Sorensen, Poul H.
Cancer cells have altered metabolism compared to normal cells, including dependence on glutamine (GLN) for survival, known as GLN addiction. However, some cancer cell lines do not require GLN for survival and the basis for this discrepancy is not well understood. GLN is a precursor for antioxidants such as glutathione (GSH) and NADPH, and GLN deprivation is therefore predicted to deplete antioxidants and increase reactive oxygen species (ROS). Using diverse human cancer cell lines we show that this occurs only in cells that rely on GLN for survival. Thus, the preference for GLN as a dominant antioxidant source defines GLN addiction. We show that despite increased glucose uptake, GLN addicted cells do not metabolize glucose via the TCA cycle when GLN is depleted, as revealed by C-13-glucose labeling. In contrast, GLN independent cells can compensate by diverting glucose-derived pyruvate into the TCA cycle. GLN addicted cells exhibit reduced PDH activity, increased PDK1 expression, and PDK inhibition partially rescues GLN starvation-induced ROS and cell death. Finally, we show that combining GLN starvation with pro-oxidants selectively kills GLN addicted cells. These data highlight a major role for GLN in maintaining redox balance in cancer cells that lack glucose-dependent anaplerosis.
Citation - WoS: 47
Citation - Scopus: 49
Monitoring the Rhizopus Oryzae Lipase Catalyzed Hydrolysis of Castor Oil by ATR-FTIR Spectroscopy
(Elsevier, 2015) Khaskheli, Abid Ali; Talpur, Farah N.; Ashraf, Muhammad Aqeel; Cebeci, Aysun; Jawaid, Sana; Afridi, Hassan Imran
A rapid and environmental friendly Attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopic method was developed for monitoring the Rhizopus oryzae lipase (ROL) catalyzed hydrolysis of castor oil in oil-in-water emulsion system. A calibration curve was constructed using partial least square (PLS) model by gravimetric addition of oleic acid (10-50%) in castor oil to detect the carbonyl absorption of free fatty acids (FFA) in the region (1690-1730 cm(-1)). The correlation co-efficient (R-2) and root mean square error of calibration (RMSEC) by PIS model were found to be 0.999 and 0.316, respectively. ROL was found to be an efficient biocatalyst to produce free fatty acids (FFA) from castor oil. Factors affecting the rate of hydrolysis such as enzyme concentration (0.01%, w/v), pH (7), temperature (37 degrees C), oil-water ratio (1:4) and reaction time (12 h) were optimized. Under all set of conditions the ROL effectively hydrolyzed castor oil up to 90% yield of fatty acids. The methodology is fairly environmental friendly in both cases, i.e. using lipase for hydrolysis of castor oil and analyzing the product through FTIR spectroscopy. (C) 2015 Elsevier B.V. All rights reserved.
Citation - WoS: 11
Citation - Scopus: 13
Prevention of Cisplatin-Induced Nephrotoxicity by Kidney-Targeted siRNA Delivery
(Elsevier, 2022) Aydin, Erkin; Cebeci, Aysun; Lekesizcan, Ayca
Cisplatin is a potent and widely used chemotherapy agent, however, nephrotoxicity limits its use. Many patients need to pause or withdraw from chemotherapy to prevent acute kidney injury. To prevent cisplatin damage, we designed chitosan/siRNA nanoparticleswhich are nontoxic and are readily taken up by HEK293 cells. The nanoparticles contained siRNA against cationic membrane transport (OCT1&2) and apoptosis related proteins (p53, PKC8, and gamma GT). In mice treated with cisplatin, serum creatinine levels increased from 15 to 88 mg/dL and blood urea nitrogen levels increased from 0.25 to 1.7 mg/dL, however, siRNA nanoparticles significantly limited these levels to 30 mg/dL and 0.55 mg/dL, respectively. Western and IHC analyses showed lower p53, PKC8, and gamma GT expressions in siRNA treated mice. Histomorphological evaluation revealed high-level protection of kidney proximal tubules from cisplatin damage. Protein expressions and extent of kidney protection were directly correlated with number of siRNA applications. Our results suggest that this novel approach for kidney -targeted delivery of select siRNAs may represent a promising therapy for preventing cisplatin-induced nephro-toxicity. Furthermore, this or other similarly sized nanocarriers could potentially be utilized to passively target kidneys for diagnostic, protective, or treatment purposes.
Citation - WoS: 3
Citation - Scopus: 3
Highly Potent New Probiotic Strains From Traditional Turkish Fermented Foods
(Springer, 2025) Yigit, Mehmet Burak; Cebeci, Aysun
Traditional Turkish fermented foods like boza, pickles, and tarhana are recognized for their nutritional and health benefits, yet the probiotic potential of lactic acid bacteria (LAB) strains isolated from them remains underexplored. Sixty-six LAB strains were isolated from fermented foods using bacterial morphology, Gram staining, and catalase activity. The isolates were differentiated at strain level by RAPD-PCR (Random Amplification of Polymorphic DNA-Polymerase Chain Reaction) and twenty-five strains were selected for further evaluation of acid and bile salt tolerance. Among these, ten strains exhibited high tolerance and were subsequently assessed for adhesion to Caco-2 colorectal carcinoma cells, antimicrobial activity, exopolysaccharide (EPS) production, lysozyme resistance, and hemolytic activity. Using k-means clustering, three strains: Lactiplantibacillus plantarum ES-3, Pediococcus pentosaceus N-1, and Enterococcus faecium N-2 demonstrated superior probiotic characteristics, including significant acid (100% survival at pH3.0) and 0.3% bile salt tolerance (57%, 64%, 67%), strong adhesion to intestinal cells (65%, 88%, 91%), high lysozyme resistance (88%, 88%, 77%), and produced high amounts of EPS. These strains show promising potential as probiotics and warrant further investigation to confirm their functional properties and potential applications.
Citation - WoS: 9
Citation - Scopus: 13
A Highly Selective Whole Cell Biocatalysis Method for the Production of Two Major Bioactive Conjugated Linoleic Acid Isomers
(Elsevier, 2013) Khaskheli, Abid Ali; Talpur, Farah N.; Demir, Ayhan S.; Cebeci, Aysun; Jawaid, Sana
Conjugated linoleic acid (CLA) is well known potential anticarcinogenic, antiatherogenic and a number of other therapeutic qualities bearing substance. In the present study we have isolated Lactobacillus plantarum from local dairy buffalo milk and used as a whole cell biocatalyst, for selective CLA isomer production from linoleic acid (LA). Quantitative analysis revealed that the cis-9, trans-11 CLA comprised of 51% (w/w), while trans-10, cis-12 CLA accounted for 49% (w/w) of total CLA produced by L. plantarum. The product formation and quantitation was monitored by the spectrophotometric method and the individual isomers separation was done with GCFID. After optimization of biotransformation conditions such as pH, LA concentration, effect of preincubation, fermentation time; the highest CLA production (19.07% conversion) was achieved at 120 h in the presence of 1.62 mg ml-1 of LA. The results revealed that the bacterium is an efficient biocatalyst for the production of two major bioactive CLA isomers using LA as a substrate. (C) 2013 Elsevier Ltd. All rights reserved.