MEHTAP KARA

Dr. MEHTAP KARA

orcid

Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 January 2020 in Toxicology Reports
Verified
Journal Article
Open access
MKMEHTAP KARA
MEHTAP KARA
EOEzgi Oztas
Ezgi Oztas
RRRabia Ramazanoğulları
Rabia Ramazanoğulları
DKDemetrios Kouretas
Demetrios Kouretas
CNCharitini Nepka
Charitini Nepka
Aristidis S. VeskoukisAristidis S. Veskoukis
Aristidis S. Veskoukis
Fungicides are used in the agricultural sector against the harmful action of fungi, however they are potential toxic agents for the environment and the living organisms. Benomyl is a widely encountered benzimidazole fungicide that exerts its toxicity via inhibiting microtubule formation in the nervous system and the male reproductive and endocrine systems, whilst it is a known teratogen. Since toxic effects of benomyl and its molecular mechanisms are not fully understood, we aimed to detect its neurotoxic potential via evaluating cytotoxicity, oxidative stress and apoptosis in SH-SY5Y cell line. The cells were incubated with benomyl in a concentration range between 1 and 6 μM for 24 h. Our results indicated a concentration-dependent enhancement of reactive oxygen species measured through flow cytometry and DNA damage evaluated via the comet assay. Additionally, it induced apoptosis in all tested concentrations. According to the findings of the present study, benomyl is a xenobiotic, which it appears to exert its toxic action via a redox-related mechanism that, finally, induces cell apoptosis and death. We believe that this study will offer further insight in the toxicity mechanism of benomyl, although further studies are recommended in order to elucidate these mechanisms in the molecular level.

1 October 2020 in Turkish Journal of Pharmaceutical Sciences
Verified
Journal Article
Closed access
MKMEHTAP KARA
MEHTAP KARA
EÖEzgi Öztaş
Ezgi Öztaş
GÖGül Özhan
Gül Özhan
Neonicotinoid insecticides, 30% of insecticides marketed worldwide, have selective toxicity on insects through α4p2 nicotinic acetylcholine receptors. Although it is known that acetamiprid exerts toxicity on several organ systems, its toxic effects on the pancreas and its mechanism of action have not been clarified yet. Therefore, in the present study, the cytotoxic and genotoxic potentials of acetamiprid on the AR42J pancreatic cell line were evaluated. The (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) (MTT) assay and comet assay were conducted for the cyto- and genotoxicity evaluations, respectively. Reactive oxygen species (ROS) production was assessed by flow cytometry and glutathione (GSH) levels were determined by ELISA for oxidative damage potential, which is thought to be an underlying mechanism of cyto-/genotoxic effects. To reveal the dose-response relationship the concentration range of 1-6 mM was selected for the assays. Cell viability decreased in a dose-dependent manner and the inhibitory concentration 50 value was calculated as 12.61 mM by the MTT assay. Acetamiprid induced DNA damage in all concentrations tested in a dose-depending manner. The mean tail intensity values were 3.84 and ≤32.96 for the control and exposure groups, respectively. There was no significant difference for ROS production; however, the GSH level was reduced at the highest concentration. It is thought that the present study will contribute to the literature due to the lack of data on the potential toxic effects of acetamiprid on the pancreas. To better understand acetamiprid toxicity, further studies including a wide range of mechanistic parameters are needed.

24 August 2021 in Biology
Verified
Journal Article
Open access
PDF file
EÖEzgi Öztaş
Ezgi Öztaş
MKMEHTAP KARA
MEHTAP KARA
TBTuğçe Boran
Tuğçe Boran
EBEnes Bişirir
Enes Bişirir
EKEcem Fatma Karaman
Ecem Fatma Karaman
GÖGül Özhan
Gül Özhan
Acetamiprid (ACE), a commonly used neonicotinoid insecticide, is correlated with neurological symptoms, immunotoxicity and hepatotoxicity. Cellular stress and damage could play an important role in ACE-induced neurotoxicity; however, its mechanism has not been fully understood. We evaluated the effects of ACE on oxidative stress, endoplasmic reticulum (ER) stress, cellular death, mRNA expression levels of related genes and protein expressions of related molecular mechanisms in SH-SY5Y human neuroblastoma cells. The half maximal inhibition of enzyme activity (IC50) value of ACE was determined as 4.26 mM after 24 h of treatment by MTT assay. We revealed an increase in reactive oxygen species (ROS) production and calcium release. Significant increases were measured in inositol-requiring enzyme 1-alpha (IRE1-α) and binding immunoglobulin protein 90 (GRP90) levels as well as mRNA expression levels of caspase 3, 4 and 9 genes indicating enhanced ER stress. Apoptosis and ER stress-related genes were significantly upregulated at ≥2 mM. Indeed, ACE caused apoptosis and necroptosis while necrosis was not observed. There was a significant increase in the protein level of mitogen-activated protein kinase-8 (MAPK8) at 4 mM of ACE while no change was seen for nuclear factor kappa-B (NF-κB) and tumor necrosis factor-alpha (TNF-α). In conclusion, increased cellular stress markers could be proposed as an underlying mechanism of ACE-induced cell death in neural cells.

12 February 2023 in Toxics
Verified
Journal Article
Open access
PDF file
CSCigdem Sevim
Cigdem Sevim
EAErol Akpınar
Erol Akpınar
EAEmrah Hicazi Aksu
Emrah Hicazi Aksu
AOAli Dogan Omur
Ali Dogan Omur
SYSerkan YILDIRIM
Serkan YILDIRIM
RERabia Nilüfer Ersoylu
Rabia Nilüfer Ersoylu
The potential health-promoting effects of probiotics against intoxication by pesticides is a topic of increasing commercial interest with limited scientific evidence. In this study, we aimed to investigate the positive effects of probiotic Saccharomyces boulardii on the male reproductive system under low dose neonicotinoid pesticide exposure conditions. We observed that acetamiprid and imidacloprid caused a degeneration and necrosis of the spermatocytes in the tubular wall, a severe edema of the intertubular region and a hyperemia. This was concomittant to increased levels of 8-hydroxy-2′-deoxyguanosine reflecting oxidative stress, and an increase in caspase 3 expression, reflecting apoptosis. According to our results, Saccharomyces boulardii supplementation mitigates these toxic effects. Further in vivo and clinical studies are needed to clarify the molecular mechanisms of protection. Altogether, our study reinforces the burden of evidence from emerging studies linking the composition of the gut microbiome to the function of the reproductive system.

1 October 2021 in Environmental Toxicology and Pharmacology
Verified
Journal Article
Closed access
CSCigdem Sevim
Cigdem Sevim
MÖMustafa Özkaraca
Mustafa Özkaraca
MKMEHTAP KARA
MEHTAP KARA
NUNergis Ulas
Nergis Ulas
AMAli sefa Mendil
Ali sefa Mendil
Aristidis TsatsakisAristidis Tsatsakis
Aristidis Tsatsakis

12 October 2024 in Nutrients
Verified
Journal Article
Open access
PDF file
GCGozde Hasbal Celikok
Gozde Hasbal Celikok
MKMEHTAP KARA
MEHTAP KARA
MGMarta Sánchez Gómez-Serranillos
Marta Sánchez Gómez-Serranillos
COClaudia Owsianik
Claudia Owsianik
MGM. Pilar Gómez-Serranillos
M. Pilar Gómez-Serranillos
AKAmjad Khan
Amjad Khan
Background: Grape seed extract (GSE) from Vitis vinifera L. is rich in polyphenols and oligomeric proanthocyanidin complexes (OPCs), and it has shown potential benefits in managing low mood and cognitive function. In this study, we investigated the potential bioactivities of Enovita®, a standardized GSE extract (GSEe herein) rich in OPCs, in key mechanistic pathways related to low mood conditions and cognitive function. Methods: In vitro assays were conducted to assess GSEe’s inhibitory effects on γ-aminobutyric acid transaminase (GABA-T) and monoamine oxidase A (MAO-A), its binding affinity to the GABA site of GABA-A receptors, and its effects on acetylcholinesterase (AChE). Its neuroprotective effects on human SH-SY5Y neuroblastoma cells under oxidative stress (induced by H2O2) were assessed using MTT and LDH release assays. Its antioxidant activities were evaluated using DPPH, ABTS, FRAP, ORAC, HORAC, total phenolic content, and TAS assays. Its cytotoxicity was also evaluated. Results: GSEe showed significant GABA-T inhibitory activity. It also exhibited MAO-A and AChE inhibition, along with moderate binding affinity to the GABA-A receptor. In neuroprotective assays, GSEe provided significant protection to SH-SY5Y cells against oxidative stress. GSEe demonstrated robust antioxidant activity in all assays, including scavenging of DPPH and ABTS radicals, high ferric-reducing power, high polyphenolic contents, and a substantial total antioxidant capacity. Conclusions: GSEe exhibits promising bioactivities, highlighting its potential as a supplement for modulating mood and enhancing cognitive function. Overall, the promising results from these in vitro studies provide a strong foundation for the continued exploration and development of GSEe as a viable natural supplement for enhancing mental health and cognitive function.