Publications by authors named "Bekir Eser"

Cello-oligosaccharides (COS) are gaining great attention for their prebiotic-like properties, e.g., boosting gut health by promoting beneficial bacteria and improving digestion.

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The Gfo/Idh/MocA family enzyme DgpA was known to catalyze the regiospecific oxidation of puerarin to 3"-oxo-puerarin in the presence of 3-oxo-glucose. Here, we discovered that D3dgpA, cloned from the human gut bacterium sp. MRG-IFC3, catalyzed the regiospecific oxidation of various -/-glycosides, including puerarin, in the presence of methyl β-D-3-oxo-glucopyranoside.

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Human gut bacterium sp. MRG-IFC3 is unique in that it is capable of metabolizing puerarin, an isoflavone -glycoside, whereas it shows broad substrate glycosidase activity for the various flavonoid -glycosides. To address the question on the substrate specificity, as well as biochemical characteristics, cell-free biotransformation of flavonoid glycosides was performed under various conditions.

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Purpose: To evaluate the shear bond strength of two different resin cements to zirconia after treatment with cold atmospheric pressure plasma (CAPP) and other surface modification methods.

Methods: 189 specimens fabricated from Vita YZ-HT zirconia discs were divided into nine surface treatment groups: (1) Untreated (U), (2) Sandblasting (S), (3) Laser (L), (4) Plasma (P), (5) Primer (PR), (6) Sandblasting + Primer (SPR), (7) Laser + Primer (LPR), (8) Plasma + Primer (PPR), (9) Laser + Plasma + Primer (LPPR). Surface roughness (Ra) and contact angles were measured (n= 10 each), and scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) analyses were performed (n= 1 each).

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Puerarin, daidzein C-glucoside, was known to be biotransformed to daidzein by human intestinal bacteria, which is eventually converted to (S)-equol. The metabolic pathway of puerarin to daidzein by DgpABC of Dorea sp. PUE strain was reported as puerarin (1) → 3''-oxo-puerarin (2) → daidzein (3) + hexose enediolone (C).

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Article Synopsis
  • * A new thermophilic laccase called LfLAC3, discovered in Lysinibaccillus fusiformis, was shown to effectively decolorize various dyes and degrade low-density polyethylene (LDPE) films.
  • * Studies revealed LfLAC3's strong robustness and versatility, with experiments indicating its ability to alter PE’s chemical structure and surface during degradation, making it a promising option for tackling these persistent pollutants.
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Enzymatic hydroxylation of fatty acids by Cytochrome P450s (CYPs) offers an eco-friendly route to hydroxy fatty acids (HFAs), high-value oleochemicals with various applications in materials industry and with potential as bioactive compounds. However, instability and poor regioselectivity of CYPs are their main drawbacks. A newly discovered self-sufficient CYP102 enzyme, BAMF0695 from Bacillus amyloliquefaciens DSM 7, exhibits preference for hydroxylation of sub-terminal positions (ω-1, ω-2, and ω-3) of fatty acids.

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Since its discovery in 2017, the fatty acid decarboxylase (FAP) photoenzyme has been the focus of extensive research, given its ability to convert fatty acids into alka(e)nes using merely visible blue light. Unfortunately, there are still some drawbacks that limit the applicability of this biocatalyst, such as poor solubility of the substrates in aqueous media, poor photostability, and the impossibility of reusing the catalyst for several cycles. In this work, we demonstrate the use of FAP in non-conventional media as a free enzyme and an immobilized preparation.

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Coabalamin-dependent -demethylase in sp. strain MRG-PMF1 was found to catalyze the unprecedented allyl aryl ether cleavage reaction. To expand the potential biotechnological applications, the reaction mechanism of the allyl aryl ether C-O bond cleavage, proposed to utilize the reactive Co(I) supernucleophile species, was studied further from the anaerobic whole-cell biotransformation.

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Article Synopsis
  • The global production of plastics has surged due to their widespread use, leading to major environmental issues from low biodegradability, especially with types like polyethylene (PE) and polystyrene (PS).
  • Various methods for recycling exist, but biodegradation is highlighted as the most eco-friendly solution to tackle plastic pollution.
  • The review discusses advances in biodegradation of PE and PS through microbial enzymes, evaluates monitoring techniques, and suggests strategies for enhancing plastic biodegradation and recycling technologies.
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Fatty acid hydratases (FAHs) catalyze regio- and stereo-selective hydration of unsaturated fatty acids to produce hydroxy fatty acids. Fatty acid hydratase-1 (FA-HY1) from Lactobacillus Acidophilus is the most promiscuous and regiodiverse FAH identified so far. Here, we engineered binding site residues of FA-HY1 (S393, S395, S218 and P380) by semi-rational protein engineering to alter regioselectivity.

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Extradiol dioxygenases (EDOs) catalyze the meta cleavage of catechol into 2-hydroxymuconaldehyde, a critical step in the degradation of aromatic compounds in the environment. In the present work, a novel thermophilic extradiol dioxygenase from Thermomonospora curvata DSM43183 was cloned, expressed, and characterized by phylogenetic and biochemical analyses. This enzyme exhibited excellent thermo-tolerance, displaying optimal activity at 50 °C, remaining >40% activity at 70 °C.

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Recently discovered endogenous mammalian lipids, fatty acid esters of hydroxy fatty acids (FAHFAs), have been proved to have anti-inflammatory and anti-diabetic effects. Due to their extremely low abundancies in vivo, forging a feasible scenario for FAHFA synthesis is critical for their use in uncovering biological mechanisms or in clinical trials. Here, we showcase a fully enzymatic approach, a novel in vitro bi-enzymatic cascade system, enabling an effective conversion of nature-abundant fatty acids into FAHFAs.

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Gut metabolism of natural products is of great interest due to the altered biological activity of the metabolites. To study the gut metabolism of the dietary furanocoumarins, the biotransformation of was studied with human gut microbiota. The major components of , including xanthotoxin (), bergapten (), imperatorin (), isoimperatorin (), oxypeucedanin (), and byakangelicol (), were all metabolized by the human fecal sample, and each furanocoumarin was also biotransformed by sp.

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Alka(e)nes are ideal fuel components for aviation, long-distance transport, and shipping. They are typically derived from fossil fuels and accounting for 24% of difficult-to-eliminate greenhouse gas emissions. The synthesis of alka(e)nes in Yarrowia lipolytica from CO-neutral feedstocks represents an attractive alternative.

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For the functional food applications, antioxidant properties and the bioactive compounds of the 23 species commercially cultivated in Thailand were studied. Total phenolic content and DPPH radical scavenging activity were determined. The concentrations of eight bioactive compounds, including curcumin (), demethoxycurcumin (), bisdemethoxycurcumin (), 1,7-diphenyl-(4,6)-4,6-heptadien-3-ol (), germacrone (), furanodienone (), zederone (), and -turmerone (), were determined from the by HPLC.

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This study aimed to investigate the impacts of finish line type and width on the fracture resistance of provisional crowns, and to determine the suitable type of crown material to use for that purpose. Chamfer and rounded shoulder preparations were done with stainless steel master models with a width of 0.6 mm and 1.

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Purpose: To evaluate the accuracy of mechanical torque rachet types based on the number of uses.

Methods: A total of 25 ratchets, including three frictional- and two spring-type torque ratchets from every mechanical torque ratchet group, were used in our study. A digital torque measurement device was used in assessing the efficiency of mechanical torque ratchets.

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Article Synopsis
  • Enzymatic conversion of fatty acids by fatty acid hydratases provides a sustainable method for producing valuable hydroxy fatty acids, but there's limited diversity in the types produced.
  • Two similar FAHs from Lactobacillus acidophilus were studied, revealing that modifications in key active-site residues can significantly improve substrate range and hydration selectivity.
  • A mutant form of one FAH showed a dramatic change in product specificity, leading to better efficiency in producing specific hydroxy fatty acids, and highlighted microalgae as a promising source of diverse fatty acids for potential applications across various industries.
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Purpose: To determine the effects of age and gender on the color distribution of the right maxillary central, lateral incisors, and canine teeth.

Materials And Methods: The tooth color was measured using the VITA Easyshade V spectrophotometer with a total of 202 volunteers (89 men, 113 women). The age distribution in this study was between 15 and 70 years old (average: 31).

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Staphylococcus aureus is one of the most important pathogen that causes community acquired and nosocomial infections worldwide. Phagocytosis by macrophages plays an important role in the first line defense against infections caused by S.aureus.

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Thiamin diphosphate is an essential cofactor in all forms of life and plays a key role in amino acid and carbohydrate metabolism. Its biosynthesis involves separate syntheses of the pyrimidine and thiazole moieties, which are then coupled to form thiamin monophosphate. A final phosphorylation produces the active form of the cofactor.

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