Browsing by Author "Gökkuş K."

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Effects of prebiotic mannanoligosaccharides (MOS) on histology and biochemical blood parameters of gilthead seabream, Sparus aurata
(2014-01-01) Gültepe N.; Kesbiç O.; Acar Ü.; Gökkuş K.; İrşad Gültepe M.; Sönmez A.; Bilen S.; Aydın S.
A 90-day growth trial was conducted to determine the effects of prebiotic mannanoligosaccharides (MOS) on the histology and biochemical blood parameters of the gilthead seabream (Sparus aurata). Two experimental diets were formulated to contain MOS (Bio-Mos®) levels of 0 and 2 g/kg. The fish averaging 172.11±13.19 g were reared in six octagonal net cages (763 m3). Fish were fed twice daily to apparent satiation. Individual body weight, weight gain, survival rate and feed conversion rate FCR were measured during the experiment. The treatments produced significant differences in body weight. and weight. gain (p<0.050) but no significant effect on the survival rates and FCR (P>0.05). At the end of the experimental period, biochemical blood parameters were analyzed. Blood urea level was significantly affected in the MOS group (P<0.05). No remarkable alterations in histological examinations were found. This study highlighted the positive effects of prebiotic MOS on protein efficiency and weight gain of gilthead seabream.
On the effect of modified carbohydrates on the size and shape of gold and silver nanostructures
(2020-07-01) Yazgan I.; Gümüş A.; Gökkuş K.; Demir M.A.; Evecen S.; Sönmez H.A.; Miller R.M.; Bakar F.; Oral A.; Popov S.; Toprak M.S.
Gold (Au) and silver (Ag) nanostructures have widespread utilization from biomedicine to materials science. Therefore, their synthesis with control of their morphology and surface chemistry have been among the hot topics over the last decades. Here, we introduce a new approach relying on sugar derivatives that work as reducing, stabilizing, and capping agents in the synthesis of Au and Ag nanostructures. These sugar derivatives are utilized alone and as mixture, resulting in spherical, spheroid, trigonal, polygonic, and star-like morphologies. The synthesis approach was further tested in the presence of acetate and dimethylamine as size-and shape-directing agents. With the use of transmission electron microscopy (TEM), selected area electron diffraction (SAED), x-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet-visible (UV-vis) absorption spectroscopy techniques, the particle size, shape, assembly, aggregation, and film formation characteristics were evaluated. NPs’ attributes were shown to be tunable by manipulating the sugar ligand selection and sugar ligand/metal-ion ratio. For instance, with an imine side group and changing the sugar moiety from cellobiose to lactose, the morphology of the Ag nanoparticles (NPs) transformed from well dispersed cubic to rough and aggregated. The introduction of acetate and dimethylamine further extended the growth pattern and morphological properties of these NPs. As examples, L5 AS, G5AS, and S5AS ligands formed spherical or sheet-like structures when used alone, which upon the use of these additives transformed into larger multicore and rough NPs, revealing their significant effect on the NP morphology. Selected samples were tested for their stability against protein corona formation and ionic strength, where a high chemical stability and resistance to protein coating were observed. The findings show a promising, benign approach for the synthesis of shape-and size-directed Au and Ag nanostructures, along with a selection of the chemistry of carbohydrate-derivatives that can open new windows for their applications.