Fikret Sari

The increasing use of pesticides in recent years is considered a threat to the environment and health. The current study intended to assess the potential phytotoxic impacts of tau-fluvalinate, a pyrethroid pesticide, on Lactuca sativa (Asteraceae) using germination and seedling development endpoints. For this purpose, germination percentage, relative seed germination, relative root growth, and germination index were determined for L. sativa seeds exposed to five different concentrations of tau-fluvalinate (12, 24, 48, 96, and 192 mg/L) for 48 h. Statistically significant differences were observed among the tested concentrations in terms of germination percentage, root and shoot length, relative seed germination, relative root growth, and germination index (p < 0.0001). Based on the calculated germination indices, the concentration of 12 mg/L was classified as non-phytotoxic but moderately inhibitory, 24 mg/L as moderately phytotoxic, and 48, 96, and 192 mg/L as highly phytotoxic. These findings indicate that tau-fluvalinate may pose environmental risks due to its acute toxic, sublethal, and phytotoxic effects, particularly at high concentrations. Furthermore, the results confirm that L. sativa is a sensitive and reliable bioindicator for assessing the phytotoxicity of synthetic pyrethroids.

As pesticides negatively affect non-target organisms, their excessive and indiscriminate use poses a threat to the environment and aquatic ecosystems. In this study, it was aimed to examine the lethal and sublethal effects of tau-fluvalinate, a pyrethroid pesticide, on the non-target organism Chironomus riparius. For this aim, acute toxicity of tau-fluvalinate was evaluated through a 96-h mortality test, and changes in the locomotor activity of C. riparius were examined after 72- and 144-h exposures to different sublethal concentrations. Mortality tests indicated that both concentration (F9, 240 = 133,80; P<0.0001; ηp2 = 0.83) and exposure duration (F3, 240 = 18,93; P<0.0001; ηp2 = 0.19) had statistically significant effects on mortality. In locomotor activity tests conducted at sublethal concentrations (2.75, 5.5, 11, and 22 µg/L) selected based on the calculated 96-h median lethal concentration (44.53 µg/L), concentration (F4, 60 = 236,7; P<0.0001; ηp2 = 0.94), exposure duration (F1, 60 = 35,48; P<0.0001; ηp2 = 0.37) and their interaction (F4, 60 = 3,629; P = 0.0103; ηp2 = 0.19) were found to have statistically significant effects on locomotor activity. As the first study to evaluate the effects of tau-fluvalinate on the non-target organism C. riparius, our findings demonstrate that tau-fluvalinate poses a considerable risk to C. riparius populations, largely due to its environmental persistence, and that its prolonged presence in aquatic ecosystems constitutes an environmental hazard.

Chironomus riparius (Insecta: Diptera) is an ecological and environmental flagship species widely distributed in organically enriched waters throughout the temperate latitudes of the Northern Hemisphere. The present study elucidates the mating system of C. riparius using molecular evidence of the reproductive strategies employed by both sexes. A total of 760 larvae from 19 egg masses collected from two different wild populations (Saraykoy and Pamukkale) in Denizli, Turkiye, were genotyped at the MSC1 and MSC4 microsatellite loci, and the number of fathers per egg mass was inferred using GERUD and COLONY. Multiple paternity was detected in all sampled egg masses from both populations, with notable differences in the mean number of fathers between them. C. riparius exhibited skewed paternity in populations with male-biased breeding sex ratios. The species is polygynandrous, with both sexes mating with multiple partners. The high frequencies of multiple paternity observed in this study likely indicate substantial genetic diversity within these populations, supporting the species? persistence across diverse ecological conditions.

Abamectin, a widely used pesticide with insecticidal, anthelmintic, and acaricidal properties, has raised safety concerns due to its toxic effects on certain non-target organisms. The toxicity of abamectin, the active ingredient in the commercial pesticide formulation Alopec?EC, was evaluated using cytogenetic and comet assays on Allium cepa root tips. Mitotic index (MI) and phase index (PI) values were used for cytotoxicity assessment. Chromosomal aberration (CA) frequencies in the dividing cells and comet data were used for genotoxicity assessment. The root growth test showed a significant concentration-based decline in root growth after abamectin exposure, with a median effective concentration (EC50) of 2.50 mg/L. Following 96-hour exposure to three concentrations of abamectin (1.25, 2.50, and 5.00 mg/L), cytogenetic and comet analyses indicated a significant concentration- and time-dependent decrease in the MI, alongside an increase in DNA damage. Additionally, there was a significant concentration-dependent rise in the total frequency of CAs. These findings show that abamectin is a pesticide with lethal effects on A. cepa root tip meristematic cells, even at lower concentrations, over prolonged exposure times, with CA-forming and DNA-damaging effects, and that it is highly cytotoxic and genotoxic.

Impaired diabetic wound healing causes foot ulcers. We investigated egg yolk oil for skin wound healing in streptozotocin (STZ) induced diabetic rats. Rats were allocated into three groups of six. Group 1, nondiabetic control group, was treated topically with 2% fusidic acid ointment. Group 2, STZ diabetic control, was treated topically with 2% fusidic acid ointment. Group 3, STZ diabetic group, was treated topically with egg yolk oil. Three days after STZ injection, two full thickness excisional skin wounds were created on the back of each animal. Wound diameter was measured for 14 days and wound contraction was calculated. Re-epithelization time also was determined. Three rats from each group were sacrificed on experimental day 7 and the remaining rats on day 14. Wound samples were examined using hematoxylin and eosin, periodic acid-Schiff, Masson’s trichrome, Taenzer-Unna orcein and toluidine blue staining. Expression of endoglin (CD105), epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF) were investigated using immunohistochemistry. Egg yolk oil increased the proliferation of epithelial cells and angiogenesis, and stimulated collagen deposition in the lesion area. Egg yolk oil increased CD105, EGF and VEGF expression in blood vessels, and EGF and VEGF expression in epidermis of the lesions. The predominant fatty acids in egg yolk oil are oleic, palmitic and linoleic, which likely were responsible for the beneficial effects of egg yolk oil on diabetic wound healing. Egg yolk oil appears to be a promising therapeutic agent for healing of diabetic wounds.

Aquatic ecosystems are recipients of various contaminants including pesticides. For many years, pyrethroid insecticides (e.g., tau-fluvalinate) have been used extensively in agricultural activities to control pests. However, they can affect not only target organisms but also non-target organisms. This study was conducted to investigate the lethal and sublethal effects of tau-fluvalinate on the non-target organism Gammarus roeseli. To this end, acute toxicity of tau-fluvalinate was determined using a toxicity test with a 96-h exposure period, and the genotoxic effects of different sublethal concentrations on hemocytes of the test organism were assessed at 24-, 96-, and 240-h exposure periods using the comet assay. Alterations in locomotor activity of the test organism in response to exposure to sublethal concentrations were evaluated at 120- and 240-h periods. The 96-h median lethal concentration (LC50) was found to be 17.29 μg/L, and tau-fluvalinate was observed to cause a significant increase in DNA damage and a significant reduction in locomotor activity at the tested sublethal concentrations (2.15, 4.30 and 8.60 μg/L). The results of this study suggest that the long-term existence of tau-fluvalinate in aquatic environments at high concentrations is a noteworthy threat to non-target organisms and that its use in agricultural activities should be reconsidered.

This study was conducted to assess the acute toxicity of three previously synthesised 5-(3′-amino-4′-arylazo-1H-pyrazole-5′-ylazo) barbituric acid dyes (dyes 1–3) using Gammarus roeseli (Crustacea: Amphipoda) and Chironomus riparius (Insecta: Diptera) and to compare their sensitivities to these dyes. The toxicity of the tested dyes was found to increase with lengthened exposure period in both bioassays. The azo dye toxicity to both species was determined to increase due to the presence of the nitro and chloro groups in the structure. G. roeseli exhibited more tolerance to the nitro group containing azo dye (dye 2) than C. riparius, whereas C. riparius exhibited more tolerance to the chloro group containing azo dye (dye 3) than G. roeseli; however, the sensitivity of two species to the azo dye without these groups (dye 1) did not significantly differ. The results suggest that the sensitivity varies depending on the species and the azo dye structure and that both species are suitable for ecotoxicological tests of the azo dyes. Nevertheless, further studies are recommended to determine all aspects of the toxicity mechanisms of these azo dyes, to investigate their degradation products and to assess their actual risk in the environment based on the results of this study. GRAPHICAL ABSTRACT

In this study, five new heterocyclic disazo dyes containing pyrazole and pyrazolone were synthesised (3a‐3e). The synthesised disazo dyes were characterised by elemental analysis and Fourier Transform–infrared and proton nuclear magnetic resonance spectroscopy. The effects of two different solvents upon the absorption ability of the dyes substituted with electron‐withdrawing and electron‐donating groups were examined in detail. In addition, the acute toxicity of each synthesised azo dye was evaluated using a short‐term bioassay with Gammarus roeseli (Crustacea: Amphipoda) for 48 hours. According to the evaluations, the dyes 3a, 3b and 3d were categorised as slightly toxic, and the dyes 3c and 3e as practically non‐toxic. Considering the toxicity of the dye 3a, it was determined that the substitution of the electron‐withdrawing group in the azo dye resulted in more toxicity, while the substitution of the electron‐donating group resulted in less toxicity. It was also found that the presence of the strongly electron‐withdrawing group resulted in the azo dye becoming more toxic in comparison with the presence of the weakly electron‐withdrawing group, but that the presence of the strongly electron‐donating group resulted in the azo dye becoming less toxic in comparison with the presence of the weakly electron‐donating group. It is contended that this study is novel and of great importance in terms of synthesising new azo dyes, investigating their absorption properties and assessing their acute toxicities.