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- ArticleYalnız künye2026Cytotoxic and apoptotic effects of Fe, Cu, and Ag nanoparticles synthesized with sage (Salvia officinalis) extract on rainbow trout gonad cell line
Kırıcı, Muammer; Erdoğan, Mehmet Kadir; Caf, Fatma; Gündoğdu, Ramazan; Taysı, Mehmet Reşit; Kırıcı, Mahinur; Sökmen, Teoman Özgür; Kaya, Bülent; Toy, Yusuf
The rapid increase in the use of nanoparticles in various sectors necessitates understanding their potential biological effects on aquatic organisms. In particular, the biosafety profiles of plant-derived biosynthetic nanoparticles, developed as environmentally friendly alternatives, are still known to a limited extent. In this study, the cytotoxic and apoptotic effects of iron (Fe), copper (Cu), and silver (Ag) nanoparticles obtained by green synthesis using sage ( Salvia officinalis ) leaf extract on rainbow trout ( Oncorhynchus mykiss ) gonad cell line (RTG-2) were investigated. The structural and morphological properties of the synthesized nanoparticles were characterized by UV–Visible spectroscopy, FT-IR, X-ray diffraction (XRD), scanning electron microscopy (SEM)-EDX, and zeta potential analyses. Cell viability and apoptosis-related protein responses were assessed following nanoparticle exposure. The results showed that all metal nanoparticles produced a concentration-dependent cytotoxic effect in RTG-2 cells. Silver nanoparticles (AgNPs) exhibited the strongest cytotoxic effect, significantly reducing cell viability, especially at concentrations of 50 µg/mL and above. Apoptosis analysis revealed that different toxicity mechanisms were activated depending on the metal type. While AgNPs strongly suppressed BCL2 expression and appeared to enhance apoptosis-related responses, CuNPs and FeNPs were mainly associated with p53-mediated cellular stress signaling. In conclusion, it was shown that sage-derived metal nanoparticles produced metal-type-specific cytotoxic and apoptotic effects in fish gonad cells; these findings highlight the necessity of species- and metal-based approaches in the environmental risk assessment of green synthesis nanoparticles.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2026Assessment of Population Parameters for Fisheries Management in a Pressured Ecosystem: A Case Study of Sapanca Lake (Türkiye)
Şen Özdemir, Nurgül; Aydın, Erdinç; Sökmen, Teoman Özgür
Sapanca Lake is a tectonic freshwater lake ecosystem whose water balance and ecological integrity are increasingly threatened by urbanization, pollution, climate change, and declining water levels. To assess recent changes in the fish community, length–weight relationships (LWRs), condition factors (CFs), sex ratios (F/M), and standing stock biomass estimates were determined for eight fish species (Blicca bjoerkna, Scardinius erythrophthalmus, Carassius gibelio, Esox lucius, Silurus glanis, Perca fluviatilis, Abramis brama and Cyprinus carpio) sampled between December 2024 and April 2025. According to standing stock biomass assessments, Cyprinus carpio showed the highest biomass (297.67 tons), while Abramis brama had the lowest (22.72 tons). Most species showed positive allometric growth (b > 3), suggesting generally favorable feeding conditions. In contrast, the main predatory species, E. lucius (b = 2.89) and Silurus glanis (b = 0.21), exhibited negative allometric growth, likely due to limitations in food availability and prey abundance. The CF values were generally >1, indicating good physiological status; however, lower CF values in A. brama (1.18) and B. bjoerkna (1.19) suggest species-specific ecological limitations. Sex ratio analysis revealed pronounced female dominance across species, ranging from complete female dominance (F/M = 1/0) in Carassius gibelio to a female-biased ratio of 1/0.04 in Scardinius erythrophthalmus, likely driven by seasonal sampling effects, sex-specific behavior, and species-specific reproductive strategies. Overall, the results indicate increasing trophic imbalance and ecological stress in Sapanca Lake, emphasizing the need for standing stock biomass assessments and ecosystem-focused fisheries management in tectonic lakes under hydrological pressure.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2026Effect of cobalt molybdate (CoMoO4) particles on the growth kinetics of Lactococcus sp. in liquid culture
Sökmen, Teoman Özgür
Lactococcus sp. is a major bacterial pathogen in aquaculture, responsible for significant economic losses worldwide. The present study aimed to investigate the effect of cobalt molybdate (CoMoO4) particles on the growth dynamics of Lactococcus sp. under liquid culture conditions. Structural characterization of CoMoO4 was performed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Molecular confirmation of the bacterial isolate was achieved through 16S rRNA gene amplification. Bacterial growth inhibition was monitored spectrophotometrically at 600 nm. The results demonstrated a concentration-dependent suppression of bacterial growth, highlighting the potential of CoMoO4 as an alternative antimicrobial agent in aquaculture.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2026Seasonal Dynamics of Gonadal Antioxidant Biomarkers Associated with Reproductive Indices in Capoeta umbla and Capoeta trutta
Şen Özdemir, Nurgül; Kırıcı, Muammer; Caf, Fatma; Güneş, Muharrem; Sökmen, Teoman Özgür; Türk, Cebrahil; Demir, Nurullah
Seasonal variability and reproductive investment influence oxidative metabolism in fish; however, the relationship between reproductive dynamics and antioxidant responses in freshwater cyprinids remains insufficiently understood. This study investigated seasonal and biological factors affecting antioxidant biomarkers in the gonads of Capoeta umbla and Capoeta trutta inhabiting the Karasu River (Türkiye). A total of 152 individuals were examined between April 2023 and March 2024, and reproductive indices (total body weight, gonad weight, and gonadosomatic index) were evaluated together with oxidative stress biomarkers, including malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and glutathione peroxidase (GPx). Multivariate analyses (PERMANOVA, SIMPER, and principal coordinate analysis) were used to determine the factors shaping oxidative responses. Females exhibited higher reproductive investment, while reproductive activity increased during spring and summer, accompanied by elevated MDA levels and antioxidant enzyme activities. PERMANOVA identified season as the primary factor explaining variation in oxidative biomarkers (p = 0.001), followed by reproductive parameters, and PCO revealed clear seasonal separation among groups. These findings indicate that oxidative balance in gonadal tissues is strongly associated with seasonal reproductive cycles and environmental variability in wild freshwater cyprinids.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2026Composition of Commercial Gillnet Catches in a Groundwater-Fed Lake: Mesh-Specific Patterns and High Representation of Non-Indigenous Carassius gibelio
Sökmen, Teoman Özgür
Small inland lakes support substantial freshwater biodiversity, but independent fish surveys may be constrained by specialised equipment, trained personnel, seasonal replication, and sustained funding. This study evaluated whether repeated observations of routine commercial gillnet catches could characterise the gillnet-catchable fish subcommunity of Çaltıcak (Taşkısığı) Lake, a shallow, approximately 90-ha groundwater-fed lake in Sakarya Province, Türkiye, and support surveillance of the non-indigenous Carassius gibelio. Fish were obtained over 17 sampling nights from 12 February to 3 June 2026 using five separate single-mesh monofilament gillnets (40, 50, 60, 75, and 80 mm mesh-bar length). Total design-based nominal mounted-area effort was 22,451.7086 m2-night, and catch was expressed as area-standardised numerical and biomass catch per unit effort (NPUE and BPUE). A total of 863 individuals from eight species were examined. Blicca bjoerkna, C. gibelio, and Scardinius erythrophthalmus were the most numerically represented species. C. gibelio constituted 26.42% of the examined catch and had a strongly female-biased catch composition (95.2% female). Smaller-bodied cyprinids occurred mainly in 40–50 mm meshes, whereas Cyprinus carpio and Silurus glanis occurred mainly in 80 and 60 mm meshes, respectively; Esox lucius was an exception, occurring mainly in 40–50 mm meshes. The combined catch corresponded to 0.038438 individuals m−2 night−1 and 0.015831 kg m−2 night−1. Approximate overnight soak duration varied seasonally from 9 to 16 h, but exact set and retrieval clock times were not recorded. Deployment coordinates were also not recorded, and sampling was confined to routine commercial fishing zones during February–June. Accordingly, the findings apply only to the gillnet-catchable fish subcommunity and must not be interpreted as a lake-wide fish-community or stock estimate. Repeated monitoring with georeferenced deployment and exact effort records would strengthen this catch-based baseline.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2026Seasonal Dominance over Morphometric Effects in Regulating Antioxidant Defense in Two Freshwater Capoeta Species
Kırıcı, Muammer; Özdemir, Nurgül Şen; Güneş, Muharrem; Sökmen, Teoman Özgür; Caf, Fatma; Türk, Cebrahil; Demir, Nurullah
Antioxidant defense systems in fish are highly sensitive to environmental variability and provide valuable indicators of physiological stress in aquatic ecosystems. This study evaluated the combined effects of seasonal variation, morphometric parameters (total length, total weight, and condition factor), sex, and species identity on oxidative stress markers and antioxidant defense responses in Capoeta umbla and Capoeta trutta collected from the Karasu River (Türkiye). Fish were seasonally sampled between April 2023 and March 2024, and malondialdehyde (MDA) levels and the activities of key antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR), were analyzed in edible muscle tissues. Length–weight relationships and Fulton’s condition factor were calculated to describe growth patterns and physiological status. The results indicated that seasonal variation was the primary factor influencing oxidative stress responses and antioxidant defense patterns in both species. Higher oxidative stress levels and increased antioxidant enzyme activities were generally observed during the summer period, reflecting physiological responses to elevated environmental temperatures. Morphometric parameters and species identity showed comparatively weaker associations with antioxidant variability. Overall, the findings highlight the dominant role of seasonal environmental dynamics in regulating oxidative balance in freshwater Capoeta species and support the use of antioxidant biomarkers as effective tools for assessing ecosystem health under changing environmental conditions.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2022Investigation of Changes in Malondialdehyde Level, Superoxide Dismutase and Catalase Activity in Liver Tissue of Capoeta umbla exposed to 2,4-Dichlorophenoxyacetic Acid
Kirici, Mahinur; Taysı, Mehmet Reşit; Kirici, Muammer; Sökmen, Teoman Özgür
In this study, changes in malondialdehyde level (MDA), superoxide dismutase (SOD) and catalase (CAT) activity in fish liver tissue were investigated by applying two doses of 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide to Capoeta umbla fish for 72 hours. Changes in MDA level, CAT and SOD activity were determined by spectrophotometric methods. As a result of the study, it was determined that there was a statistically significant increase in MDA level, CAT and SOD activity in C. umbla liver tissue exposed to different doses of herbicide (p < 0.05). It was observed that 2,4-D herbicide disrupted the oxidant/antioxidant balance in fish liver tissue. However, these two antioxidant enzymes, which are the primary defense mechanism, appear to be resistant to the toxic effect of 2,4-D.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2020Polystyrene nanoplastics (20 nm) are able to bioaccumulate and cause oxidative DNA damages in the brain tissue of zebrafish embryo (Danio rerio)
Sökmen, Teoman Özgür; Sulukan, Ekrem; Türkoğlu, Medine; Baran, Alper; Özkaraca, Mustafa; Ceyhun, Saltuk Buğrahan
Nano-sized plastic particles formed from both daily use plastics and its debris have become a potential health and environmental problem due to features such as transportation through food webs and maternal transfer. Although many studies on the toxicity of plastics exist more detailed and molecular studies are needed to evaluate and review the effects of plastics especially in nano-size range. For this purpose, we have microinjected polystyrene nanoplastics (PNP) (20 nm) to the zebrafish embryo, which is one of the best model organisms for developmental toxicity studies, to simulate intake with food or maternal. Survival, hatching and malformations evaluated during the experimental period (120 h). Moreover, we have aimed to put forth the presence of reactive oxygen species (ROS) and apoptosis signalling accumulation in the body in addition to bioaccumulation of PNP and immunochemical toxicity (8-OHdG) on the brain of zebrafish larvae at the 120th hour. According to results, it has been demonstrated that 20 nm diameter PNP can reach the brain and bioaccumulate there, moreover lead to oxidative DNA damage in the brain regions where it bioaccumulates. Here we have also imaged the PNP from a vertebrate brain via transmission electron microscopy (TEM) for the first time. As a result of these, it has been detected increasing mortality and prevailing abnormalities in addition to excessive ROS and apoptosis in especially the brain. As a conclusion, obtained data have suggested that precautions, on the use and contamination of the plastic product, to be taken during both pregnancy and baby care/feeding are important for the health of the baby in future.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2018Determination of Heavy Metal Levels in Water, Sediment and Capoeta umbla Tissues of Karasu River (Erzincan)
Sökmen, Teoman Özgür; Güneş, Muharrem; Kirici, Muammer
In this study, it was aimed to determine the accumulation levels of some metals (Aluminum (Al), Arsenic (As), Chromium (Cr), Copper (Cu), Ferrois (Fe), Manganese (Mn), Nickel (Ni), Lead (Pb) and Zinc (Zn)) in the muscle, liver and gill tissues of the Capoeta umbla fishes caught in the water, sediment and riverbed of Karasu River. For this purpose, water temperature, pH and dissolved oxygen values were measured. As a result of water analysis, the maximum amount of As was measured, but Al, Fe, Pb and Zn metals could not be detected in water. However, the relationship between the metals detected in water and the measured temperature, pH and dissolved oxygen values in water were compared. As a result of the sediment analysis, the highest accumulation was measured in Fe metal, whereas Al, Cu and Mn metals were not detected. In fish tissues, accumulation of all metals was detected. It has been determined that metals generally accumulate more in the liver tissue than other tissues. While the maximum accumulation in all tissues was measured in Fe metal, the lowest accumulation in all tissues was seen in Pb metal. In addition, the relationship between the metal levels detected in fish and the weight and length of fish was investigated. The quantities of metals identified in water, sediment and fish tissues have been compared with acceptable values determined by national and international agencies and assessed whether they are detrimental to the health of humans or aquatic organisms.
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