Browsing by Author "Askin, Hakan"

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Karasu Nehri (Erzurum) Havzasında Yaşayan Pelophylax Ridibundus (Anura: Ranidae) Kurbağalarında Kirliliğin Neden Olduğu Periferal Eritrositik Çekirdek Anormalliklerinin Tespiti
(2015) Askin, Hakan; Ozkan, Hakan; Çolak, Suat; Şişman, Turgay; Turkez, Hasan; İncekara, Ümit
Erzurum ovasının tek nehri olan Karasu Nehri, Fırat Nehri'nin kaynağını oluşturmaktadır. Nehirde tarımsal, endüstriyel ve evsel atıkların karışması sonucu ciddi bir çevresel kirlilik durumu söz konusudur. Bu çalışmanın amacı nehrin metallerle kirlenmiş ve kirlenmemiş bölgelerinde yaşayan ova kurbağalarındaki (Pelophylax ridibundus) genotoksik etkileri araştırmaktır. Kirliliği tespit etmek için nehrin yüzey suyu örneklerinde ağır metallerin konsantrasyonları ölçülmüştür. Kurbağalarda genotoksisite mikro çekirdek (MÇ) ve diğer çekirdek anormalliklerinin (ÇA) oluşumuna bakılarak tespit edilmiştir. MÇ ve böbrek şekilli çekirdek, çentikli çekirdek ve loplu çekirdek gibi diğer ÇA oluşumları kurbağaların eritrositleri kullanılarak belirlenmiştir. Kirlenmiş bölge kurbağalarının kanlarında MÇ ve ÇA frekansı temiz bölge kurbağalarına göre önemli ölçüde arttığı bulunmuştur. Bu artış ile nehrin kirlenmiş olma durumu arasında kuvvetli ilişkinin olduğu sonucuna varılmıştır. Yüksek ağır metal seviyesinin toksisiteye yol açtığı ve tespit edilen genotoksisitenin endüstriyel, tarımsal ve evsel aktivitelerle ilgili olabileceği kanaatine varılmıştır.
Naringenin, Hesperidin and Quercetin Ameliorate Radiation-Induced Damage in Rats: In Vivo and In Silico Evaluations
(Wiley-V C H Verlag GmbH, 2024) Uguz, Handan; Avci, Bahri; Palabiyik, Esra; Sulumer, Ayse Nurseli; Ozmen, Hilal Kiziltunc; Demir, Yeliz; Askin, Hakan
In this study, we sought to determine how well naringenin, hesperidin, and quercetin prevented damage brought on by radiotherapy. During the investigation, 48 adult female Sprague Dawley rats were used. Eight groups of eight rats each were formed by randomly assigning the rats to the groups. The normal control group was represented by Group 1. Group 2 rats were those that received a dose of 15 Gray (Gy) of radiotherapy. The rats assigned to Group 3 received only Naringenin, whereas those assigned to Group 4 received only quercetine, and those assigned to Group 5 received only hesperidin. Rats in Group 6, 7 and 8 were received naringenin, quarcetin and hesperidin at a dose of 50 mg/kg daily for one week prior to radiotheraphy exposition. After radiotheraphy and phenolic compounds rats were sacrificed and some metabolic enzyme (aldose reductase (AR), sorbitol dehydrogenase (SDH), paraoxonase-1 (PON1), butyrylcholinesterase (BChE) and glutathione S-transferase (GST)) activity was determined in eye and brain tissues. It was found that phenolic compounds have protective effect against radiation-induced damage because of their anti-diabetic antioxidant and anti-inflammatory properties. In addition, hesperidin was found to be superior to quercetin and naringenin in terms of enzyme activity efficacy. Furthermore, hesperidin exhibited favorable binding affinity for BChE in silico compared to other enzymes. image
Nitric Oxide: A Novel Inducer for Enhancement of Microbial Lipase Production
(Springer, 2016) Taskin, Mesut; Unver, Yagmur; Yildiz, Melike; Ortucu, Serkan; Askin, Hakan
The purpose of this study was to elucidate whether exogenous nitric oxide (NO) has a potential beneficial effect on lipase production capacity of some microorganisms. Sodium nitroprusside (SNP) was used as an exogenous NO donor in production medium. In comparison with the control (0 nM SNP), SNP concentrations from 10 to 100 nM induced lipase production in mesophilic bacterium Bacillus subtilis and cold-adapted yeast Yarrowia lipolytica. Especially, the maximum lipase activities for Y. lipolytica (81.2 U/L) and B. subtilis (74.5 U/L) were attained at 30 and 50 nM SNP concentrations, respectively. When compared to the control, the optimal SNP concentrations resulted in about 5.14 and 2.27-fold increases in lipase activities of B. subtilis and Y. lipolytica, respectively. Besides, it was found that the optimal SNP concentrations provided shorter incubation periods for lipase production. Conversely, no significant positive effect of exogenous NO on lipase production was determined for thermophilic bacterium Geobacillus stearothermophilus. This study showed for the first time that exogenous NO could be used as an inducer in the production of microbial lipases.