Yazar "Sevgiler, Yusuf" seçeneğine göre listele

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    Chemical and biological characteristics of propolis from Apis mellifera caucasica from the Ardahan and Erzurum provinces of Turkey: a comparative study
    (Inst Medical Research & Occupational Health, 2021) Arslan, Mehmet; Sevgiler, Yusuf; Guven, Celal; Murathan, Zehra Tugba; Erbil, Nurcan; Yildirim, Deniz; Buyukleyla, Mehmet
    The aim of this study was to compare the biological activities of ethanolic propolis extracts of Apis mellifera caucasica obtained from Ardahan and Erzurum provinces of Turkey. Samples were tested for antioxidant, anticytotoxic, anticarcinogenic, antibacterial, and antifungal potentials using different techniques. Propolis samples from the two provinces had different mineral and organic compositions related to their geographical origin. The ferric reducing antioxidant power (FRAP) test showed superiority of Ardahan propolis over the Erzurum. Regardless of origin and the presence of mitomycin C in the culture medium, propolis enhanced human peripheral lymphocyte viability, which depended on the duration and propolis concentration. Antiperoxidative activity on MCF-7 breast cancer cells was concentration-dependent. Erzurum propolis showed the highest anticarcinogenic activity at the concentrations of 62.5 mu g/mL and 125 mu g/mL, which dropped at higher concentrations. All propolis samples also showed antibacterial activity against the tested human pathogens similar to ampicillin and penicillin controls, except for Pseudomonas aeruginosa. However, they did not exert any antifungal activity against Candida albicans and Yarrowia lipolytica. In conclusion, propolis samples from both provinces showed promising biological activities, but further research should focus on finding the right concentrations for optimal effect and include the cell necrosis pathway to get a better idea of the anticarcinogenic effects.
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    Diyabette Leptin Hormonun Olası Etkileri
    (2019) Taşkın, Eylem; Güven, Celal; Kaya, Salih Tunç; Sevgiler, Yusuf
    Şeker hastalığı olarak bilinen diyabet, çeşitli komplikasyonları (kalp ve dolaşım hastalıkları, kanser ve buna benzerhastalıklar) beraberinde getiren, insan hayatını olumsuz yönde etkileyen metabolik bir hastalıktır. Genel olarakdiyabet tip I ve tip II olmak üzere iki büyük alt grupta toplanan bir hastalıktır. Tip I diyabette beta (?) hücrelerininapoptoz ile kaybı insülin salgısının azalmasında önemli bir mekanizmadır. Leptin de insülin gibi antiapoptotik veproliferatif hormonlardan biridir. Dahası düşük leptin ve insülin tedavisinin sadece yüksek doz insülin kullanımınaoranla kan şekerinin tamponlanmasında daha etkili olduğu bildirilmektedir. Fakat leptinin tip I diyabetteki buetkisi/etkileri hala gizemini korumaktadır. Leptinin tip I diyabetteki önemli etkisinden biri de yağların ?oksidasyonunun artmasına neden olarak, kan şekerinin tamponlanmasını da sağları. Bu da insülin direncininoluşmasının azalmasına neden olmaktadır. Ayrıca leptinin insülinin anabolik etkilerini taklit ettiği gibi diyabettemeydana gelen ketoasidozu önlediği de vurgulanmaktadır. Dolayısıyla leptin tedavisi, zorunlu yüksek doz insülinkullanımı azaltılmasına olanak tanıyabilmektedir. Bu derleme, literatürdeki leptin ve diyabet arasındaki bukarmaşık ilişkinin mekanizmasının aydınlatılmasında önemli bir katkı sağlayabilecek potansiyele sahiptir.
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    Effects of Different Ammonia Levels on Tribenuron Methyl Toxicity in Daphnia magna
    (Springer, 2021) Over, Sevgi Basalan; Guven, Celal; Taskin, Eylem; Cakmak, Arif; Benli, Petek Piner; Sevgiler, Yusuf
    The present study investigates the toxicity of the herbicide tribenuron methyl (TBM) as an anthropogenic agent and ammonia as an abiotic factor on Daphnia magna at environmentally relevant concentrations. These stressors may coexist in surface waters in agricultural regions. To achieve this objective, D. magna were exposed to TBM at a nominal concentration of 0.81 mu g/L in association with a low ammonia (LA) concentration of 0.65 mg/L and a high ammonia (HA) concentration of 1.61 mg/L in acute toxicity tests of 96-h duration and chronic toxicity tests of 21-day duration. The D. magna also were exposed to TBM, HA, and LA singly. The D. magna were analysed for various biomarkers of sublethal toxicity. Glutathione peroxidase (GPx), glutathione S-transferase (GST), cholinesterase (ChE) enzyme activities, and levels of thiobarbituric acid reactive substances (TBARS) and total protein were determined spectrophotometrically. Mitochondrial membrane potential (MMP) was analysed by microscopy with fluorescence staining. Cytochrome c and 5 ' AMP-activated protein kinase (AMPK) were analysed by Western blotting. Morphometric properties were examined microscopically. This is the first study in which AMPK, an indicator of intracellular energy, was measured in D. magna. GST and ChE enzyme activities and TBARS and total protein levels did not change during acute exposures (i.e., 96 h) in all treatments. GPx activity increased in D. magna from the HA + TBM treatment compared with single-exposure groups. The level of cytochrome c protein was elevated in D. magna from the LA and LA + TBM treatments. AMPK protein levels increased in all treatments with daphnids, except in the LA group. MMP was depolarised in D. magna from all treatments, whereas the most notable change was observed in HA + TBM mixture group in chronic exposures. The results show that GST and ChE may not be sensitive biomarkers for evaluating the sublethal toxic effects to D. magna exposed to environmentally relevant concentrations of ammonia and TBM. Acute and chronic exposure to ammonia and TBM probably caused an energetic crisis in D. magna. Therefore, AMPK and MMP are promising biomarkers for these toxicants.
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    HMGB1’in Kanser ve Tedavisiyle İlişkisi
    (2019) Taşkın, Eylem; Güven, Celal; Kaya, Salih Tunç; Sevgiler, Yusuf
    Yüksek mobilite grup kutusu 1 (HMGB1) histon olmayan DNA proteini olup, kısaca DAMP olarak ifade edilen(Damage-associated molecular pattern) tehlike sinyali veya alarmı olarak görev yapar. Hasarlanmış veya kanserlihücrelerden salınan HMGB1, gelişmiş glikasyon son ürünleri için reseptör (RAGE) ve Toll benzeri reseptörlerine(TLRs) bağlanarak mitojenle aktive olan kinaz (MAPK)’ları aktive ederek hücre içi etkilerini oluşturur. HMGB1kanser ilaçlarına karşı gelişen dirençte önemli rol oynar. Aynı zamanda, yumuşak doku kanserlerine karşıkullanılan ilaçlardan biri olan adriyamisinin (ADR) neden olduğu kalp yetmezliğinin gelişiminde de önemli roloynağına dair kanıtlar mevcuttur. Dolayısıyla HMGB1 kanser tedavisinde ilaçlara karşı gelişen direncin ve/veyailacın toksik etkisine karşı iyi bir terapötik ajan adayıdır. Bu derlemenin amacı, HMGB1 ile kanser ve tedavisindekullanılan bir ilaç olan ADR arasındaki ilişkiyi açıklamaktır.
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    Oxidative and apoptotic effects of fluoxetine and its metabolite norfluoxetine in Daphnia magna
    (Inst Medical Research & Occupational Health, 2020) Over, Sevgi Basalan; Guven, Celal; Taskin, Eylem; Sevgiler, Yusuf
    The aim of this study was to investigate the oxidative and apoptotic potential of fluoxetine, a widely used antidepressant in Turkey and the world. and of its metabolite norfluoxetine on a model non-target organism, Daphnia magna to see how exposure to this group of antidepressants (specific serotonin reuptake inhibitors) could affect the aquatic environment in which they end up. Juvenile D. magna specimens were chronically exposed to fluoxetine and norfluoxetine alone and in combination at concentrations found in the aquatic environment (0.091 and 0.011 mu g/L, respectively) and to their 10-fold environmental concentrations for 21 days. Another group of 17-day-old animals were subacutely exposed to 100-fold environmental concentrations for four days. After exposure, we measured their glutathione peroxidase (GPx) and cholinesterase (ChE) activities, thiobarbituric acid-reactive substances (TBARS), and total protein content spectrophotometrically, while mitochondrial membrane potential (MMP) was analysed by fluorescence staining, and cytochrome c and ERK1/2 protein content by Western blotting. This is the first-time cytochrome c and ERK1/2 were determined at the protein level in D. magna. We also measured their carapace length, width. and caudal spine length microscopically. At environmental concentrations fluoxetine and norfluoxetine caused an increase in ChE activity and brood production. They also caused a decrease in juvenile carapace length, width, and caudal spine length and depolarised the mitochondrial membrane. At 10-fold environmental concentrations. GPx activity, lipid peroxidation levels. cytochrome c. and ERK1/2 protein levels rose. The most pronounced effect was observed in D. inagna exposed to norfluoxetine. Norfluoxetine also decreased brood production. Similar effects were observed with subacute exposure to 100-fold environmental concentrations. However, total protein content decreased. All this confirms that fluoxetine and norfluoxetine have oxidative and apoptotic potential in D. magna. Daphnia spp. have a great potential to give us precious insight into the mechanisms of environmental toxicants, but there is still a long way to go before they are clarified in these organisms.