Dataset of Age- and sex-specific toxicity of Panagrellus redivivus

Description

Our study hypothesized that the toxicity of zinc oxide (ZnO) nanoparticles (NPs) on the nematode Panagrellus redivivus is influenced by particle size, nematode sex, and developmental stage. The data set comprises mortality rates of P. redivivus exposed to ZnO NPs at two nominal particle sizes (15 nm and 140 nm) across a range of concentrations (0 to 100 mg/L). Mortality was assessed for different developmental stages (juvenile stages J2, J3/J4, and adults) and separately for males and females to identify inter-age and inter-sex differences. ZnO NP suspensions were prepared and characterized before exposure experiments, with scanning electron microscopy (SEM) used to confirm particle size distribution and dissolution properties in exposure media. Contrary to initial expectations, 140 nm ZnO NPs exhibited higher toxicity than 15 nm ZnO NPs. The elevated toxicity of 140 nm ZnO is likely attributable to its irregular morphology and increased ion release compared to 15 nm ZnO. Male nematodes were more sensitive to 15 nm ZnO at higher concentrations, with significantly higher mortality rates compared to females. These results suggest that sex-based physiological differences, such as surface area-to-volume ratios and metabolic activity, may influence NP uptake and toxicity. Early larval stages (J2) showed the highest mortality across both particle sizes and concentrations. In contrast, older juveniles (J3/J4) and adults exhibited lower mortality rates, highlighting developmental stage as a critical factor in toxicity sensitivity. The observed toxicity patterns indicate that ZnO NP toxicity is not solely dependent on size but also on particle morphology and dissolution properties. The greater sensitivity of J2 larvae suggests that smaller body size and less developed physiological defenses may make early life stages more susceptible to nanoparticle stress. Additionally, the heightened sensitivity of males to 15 nm ZnO underscores the importance of considering sex-specific responses in toxicity assessments.

Steps to reproduce

Panagrellus redivivus, a bacterivore nematode, was used in dose-response assays for inter-age testing. The test system was modified from published methodologies (Hrács et al., 2018; Kiss et al., 2018; Ma et al., 2014). 100 random adult females were cultured on petri dishes from a mixed population. Based on Mcinnis (1997), we chose fertilized females with thicker, darker, more granular bodies due to eggs, embryos, and J1 larvae. After 20 hours, only J2 larvae remained after removing adult females. We let the first synchronized age group develop on oatmeal-kefir for 96 hours. At experiment hour 76, the second synchronous culture was prepared. A representative from each culture was measured 20 hours later to identify the developmental phases of the synchronized age groups (Fig. 1). The 20-hour culture contained J2 larvae (250-350 μm) and the 96-hour culture had J3 and J4 larvae (350-850 μm). Adult males and females were separated from the strain culture (size > 850 μm). Our experiment had three age groups. A Bioster S.p.A. (Italy) 96-well microplate received the animals. Five individuals per concentration were tested for acute mortality in Milli-Q water test media with animals. 160 µl Milli-Q water was introduced to each well, followed by 160 µl ZnO solutions. Four replicates and a negative control (320 μl Milli-Q water) were used for each concentration. The thermostat was set to 20 ± 1 C for dark incubation of the microplates. Using an Olympus SZH 10 transmission stereomicroscope, survivors were tallied at the end of the experiment. Motionless people were dead after exposure. Intersex tests: Samples were obtained from the oatmeal medium culture surface and placed in a Milli-Q water dish for the experiments above. Bakonyi et al. (1995) used morphology to separate mature men and females from the mixed population. Most men are smaller than women. The ventral midline houses the female vulval opening. The male opening is near the back, where the short, curved mating spine is visible. Sorting was done using an automated pipette, aspirating animals with 30 μl of liquid. Sorted males and females were in a Milli-Q water dish. Five individuals of each concentration were transferred to a 96-well microtitration plate in four duplicates, totaling 140. From then on, the test followed the age group test procedure. The effect of dissolved zinc ions was controlled with ZnCl2 (67.68 mg Zn/l). Adjusted for mean dissolving rates, the concentrations reflected dissolved Zn ions at 0.13, 0.26, 0.53, 1.06, 2.12, and 4.23 mg Zn/l. After 24 hours, 10,04 mg Zn/l ZnO particle concentration had 4,23 mg Zn/l mean dissolved Zn ion. Survival was compared to ZnO particle (15 and 140 nm) toxicity in an acute mortality set up. Only adults participated in this study. Five individuals of each concentration were transferred to a 96-well microtitration plate in four duplicates. It now used the same procedure as the age and sex group tests.

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Funders

• University Research Scholarship Programme of the Ministry for Culture and Innovation

  Grant ID: EKÖP-MATE/2024/25/K
• Magyar Agrár- és Élettudományi Egyetem

  Pest County, Hungary

  Grant ID: Flagship Research Groups Programme

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