Browsing by Author "Yetiman, Ahmet E."

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Citation - WoS: 24
Citation - Scopus: 31
Characterization of Genomic, Physiological, and Probiotic Features Lactiplantibacillus Plantarum DY46 Strain Isolated From Traditional Lactic Acid Fermented Shalgam Beverage
(Elsevier, 2022) Yetiman, Ahmet E.; Keskin, Abdullah; Darendeli, Busra Nur; Kotil, Seyfullah Enes; Ortakci, Fatih; Dogan, Mahmut
Lactiplantibacillus plantarum is a significant probiotic where it could be found in ubiquitous niches. In this study, a new Lb. plantarum strain DY46 was isolated from a traditional lactic-acid-fermented beverage called shalgam. The whole genome of the DY46 was sequenced and obtained sequences were assembled into a 3.32 Mb draft genome using PATRIC (3.6.8.). The DY46 genome consists of a single circular chromosome of 3,332,827 bp that is predicted to carry 3219 genes, including 61 tRNA genes, 2 rRNA operons. The genome has a GC content of 44.3% includes 98 predicted pseudogenes, 25 complete or partial transposases and 3 intact prophages. The genes encoding enzymes related in the intact EMP (Embden-Meyerhof-Parnas) and PK (phosphoketolase) pathways were predicted using BlastKOALA which is an indicator of having facultative heterofermentative pathways. DY46 genome also predicted to carry genes of Pln E, Pln F and Pln K showing the antimicrobial potential of this bacterium which can be linked to in vitro antagonism tests that DY46 can inhibit S.enterica sv. Typhimurium ATCC14028, K. pneumonie ATCC13883, and P. vulgaris ATCC8427. Moreover, it is determined that all resistome found in its genome were intrinsically originated and the strain was found to be tolerant to acid and bile concentrations by mimicking human gastrointestinal conditions. In conclusion, L. plantarum DY46 is a promising bacterium that appears to have certain probiotic properties, confirmed by "in vitro" and "in silico" analyses, and is a potential dietary supplement candidate that may provide functional benefits to the host.
Citation - WoS: 2
Citation - Scopus: 2
Biochemical Characterization and Genome Analysis of Pseudomonas Loganensis Sp. Nov., a Novel Endophytic Bacterium
(Wiley, 2025) Karaman, Melisa Z.; Yetiman, Ahmet E.; Zhan, Jixun; Fidan, Ozkan
Pseudomonas species are highly adaptable, thriving in diverse environments and exhibiting remarkable genetic and metabolic diversity. While some strains are pathogenic, others have significant ecological and industrial applications. Bioinformatics and biochemical analyses, including antibiotic sensitivity testing, revealed that Pseudomonas loganensis sp. nov. can tolerate NaCl concentrations up to 5% and pH ranges between 5 and 9. Antibiogram results corroborated genome data, demonstrating resistance to vancomycin, ampicillin, methicillin, oxacillin, and penicillin G. Phylogenetic analysis based on 16S rRNA, rpoB, rpoD, and gyrB genes, combined with average nucleotide identity (ANI) comparisons, confirmed P. loganensis sp. nov. as a novel species within the Pseudomonas genus. Genome analysis further revealed the presence of turnerbactin and carotenoid gene clusters. Turnerbactin, known to contribute to nitrogen fixation in plants, highlights the strain's potential as a biofertilizer. Additionally, the carotenoid gene cluster suggests potential applications in industrial carotenoid production. The discovery of a trehalose synthase (treS) gene indicates the capability for one-step conversion of maltose into trehalose, underscoring its potential utility in trehalose production.
Citation - WoS: 23
Citation - Scopus: 26
In Silico Analysis of Bacteriocins From Lactic Acid Bacteria Against SARS-CoV
(Springer, 2023) Erol, Ismail; Kotil, Seyfullah Enes; Fidan, Ozkan; Yetiman, Ahmet E.; Durdagi, Serdar; Ortakci, Fatih
The COVID-19 pandemic caused by a novel coronavirus (SARS-CoV-2) is a serious health concern in the twenty-first century for scientists, health workers, and all humans. The absence of specific biotherapeutics requires new strategies to prevent the spread and prophylaxis of the novel virus and its variants. The SARS-CoV-2 virus shows pathogenesis by entering the host cells via spike protein and Angiotensin-Converting Enzyme 2 receptor protein. Thus, the present study aims to compute the binding energies between a wide range of bacteriocins with receptor-binding domain (RBD) on spike proteins of wild type (WT) and beta variant (lineage B.1.351). Molecular docking analyses were performed to evaluate binding energies. Upon achieving the best bio-peptides with the highest docking scores, further molecular dynamics (MD) simulations were performed to validate the structure and interaction stability. Protein-protein docking of the chosen 22 biopeptides with WT-RBD showed docking scores lower than -7.9 kcal/mol. Pediocin PA-1 and salivaricin P showed the lowest (best) docking scores of - 12 kcal/mol. Pediocin PA-1, salivaricin B, and salivaricin P showed a remarkable increase in the double mutant's predicted binding affinity with -13.8 kcal/mol, -13.0 kcal/mol, and -12.5 kcal/mol, respectively. Also, a better predicted binding affinity of pediocin PA-1 and salivaricin B against triple mutant was observed compared to the WT. Thus, pediocin PA-1 binds stronger to mutants of the RBD, particularly to double and triple mutants. Salivaricin B showed a better predicted binding affinity towards triple mutant compared to WT, showing that it might be another bacteriocin with potential activity against the SARS-CoV-2 beta variant. Overall, pediocin PA-1, salivaricin P, and salivaricin B are the most promising candidates for inhibiting SARS-CoV-2 (including lineage B.1.351) entrance into the human cells. These bacteriocins derived from lactic acid bacteria hold promising potential for paving an alternative way for treatment and prophylaxis of WT and beta variants.
Pangenome Analysis and Genome-Guided Probiotic Evaluation of Cyclic Dipeptides Producing Levilactobacillus Brevis DY55bre Strain From a Lactic Acid Fermented Shalgam to Assess Its Metabolic, Probiotic Potentials, and Cytotoxic Effects on Colorectal Cancer Cells
(Springer, 2025) Yetiman, Ahmet E.; Horzum, Mehmet; Kanbur, Ertan; Cadir, Mehmet; Bahar, Dilek; Gurbuz, Serife; Akbulut, Mikail
This study investigates the genetic, metabolic, and probiotic characteristics of Levilactobacillus brevis DY55bre, a strain isolated from the traditional Turkish fermented beverage, shalgam. Whole-genome sequencing revealed a circular genome of 2.485 Mb with a GC content of 45.72%, predicted 2791 genes, and multiple CRISPR-Cas systems. Pangenome analysis demonstrated an open structure, with 18.9% core genes and 103 strain-specific genes, highlighting its genetic diversity. The DY55bre exhibits heterofermentative carbohydrate metabolism due to the presence of the araBAD operon and the lack of 1-phosphofructokinase (pfK) and fructose-1,6-bisphosphate aldolase enzymes. Probiotic evaluation revealed firm survival under simulated gastrointestinal conditions, including resistance to acidic pH (as low as 3.0) and bile salts (up to 1%), along with significant adhesion to intestinal epithelial cell lines (HT29;59.3%, Caco-2;87%, and DLD-1;60.8%). The strain exhibited high auto-aggregation (84.55%) and cell surface hydrophobicity (56.69%), essential for gut colonization. Safety assessments confirmed its non-hemolytic nature and absence of horizontally acquired antibiotic resistance genes. Notably, GC-MS analysis identified bioactive cyclic dipeptides, Cyclo(D-Phe-L-Pro) and Cyclo(L-Leu-L-Pro), which demonstrated cytotoxic effects against colorectal cancer cell lines, with IC50 values of 7.71 mg/mL for HT29 and 3.19 mg/mL for DLD-1. The cell-free supernatant exhibited antimicrobial activity against pathogens, likely due to the synergistic effects of cyclic dipeptides, organic acids, and other metabolites. Antioxidant assays revealed significant ABTS+ (76.63%) and DPPH (34.25%) radical scavenging activities, while cholesterol assimilation tests showed a 27.29% reduction. These findings position the DY55bre as a promising candidate for functional foods, nutraceuticals, and therapeutic applications, warranting further in vivo validation.