Effects of Perfluoro Organic Compound Toxicity on Nematode Caenorhabditis elegans Fecundity

Toxicity studies using the nematode Caenorhabditis elegans (C. elegans) as a model organism have shown that perfluoro organic compounds have sub-lethal toxicity at the 10 pM-100 nM range on multi-generation assays. We examined the acute lethal toxicity and multi-generational sublethal toxicity (fecundity and reproduction) of perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and salts of perfluoro-1-octansulfonic acid (PFOS) using 1.7% agar Nematode Growth Medium (NGM) plates. The fluorine compounds affected the fecundity of C. elegans at concentrations 105- to 108-fold lower than the median effective concentrations (EC50). In particular, worm abundance during the first generation did not differ significantly from controls, while in contrast, the number of worms in the fourth generation at 10 pM PFOS-tetraethylammonium (TEA) decreased significantly to about 50% of control (p < 0.01) and the number of eggs and worms in the fourth generation at 1 nM PFNA decreased significantly to about 30% of control (p < 0.01). However, no dose-response relationship was observed in this study. We confirmed that perfluoro organic compounds strongly disrupt fecundity in C. elegans

Ecotoxicological Effect of Polycyclic Musks on Caenorhabditis elegans

The polycyclic musks (PCMs), 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphtha-lene (AHTN) and 1,3,4,6,7,8-hexahydro-4,6,6,7,8-hexamethylcyclopenta-γ-2-benzopyran (HHCB), are widely used as fragrance compounds in laundry detergents, soaps and cosmetics. To assess the potential toxicological effects associated with AHTN and HHCB, Caenorhabditis elegans (C. elegans) was used as a model organism for eco-toxicity testing. We examined acute toxicity using 50% lethal concentrations (LC50) after 24 hr PCM exposure and also examined changes in the test endpoints of growth and maturation such as body length, percentage of gravid worms and fecundity. The LC50 for C. elegans was found to be more than 255.2 mg/l for AHTN and 194.6 mg/l for HHCB. In growth tests, the lowest observed effect concentrations (LOEC) in C. elegans for AHTN and HHCB were 12.8 mg/l and 9.8 mg/l, respectively. In maturation tests, LOECs were estimated at 6.4 mg/l for AHTN and 9.8 mg/l for HHCB. In reproduction tests, while maximum LOECs of 19.5 mg/l were observed for HHCB, concentrations of more than 25.5 mg/l were obtained for AHTN

Effect of Bisphenol A on the Feeding Behavior of Caenorhabditis elegans

We observed and evaluated the feeding behavior of the free-living nematode Caenorhabditis elegans (C. elegans) after exposure to bisphenol A (BPA) and nonylphenol (NP). Exposed organisms were transferred to chemical-free culture medium and their attainment levels (the number of worms reaching the food source divided by the total number of worms on the Petri plate) were recorded after 2, 4, 6, 8, and 24 hr. Results showed a significant decrease in the attainment level of worms exposed to 10 μM and 0.1 μM BPA. However, there was a slight increase in the attainment level of nematodes treated with 1 μM NP. These results differ from previous studies showing NP as being more lethal to nematodes than BPA

A Multi-Generation Sublethal Assay of Phenols Using the Nematode Caenorhabditis elegans

The nematode Caenorhabditis elegans (C. elegans) was used for a multiple-generation toxicity bioassay of phenols. We examined the sublethal toxicity (fecundity and reproduction) of bisphenol A (BisA), 4-(1-adamantyl) phenol (Adp), and 4,4′-(1,3-adamantanediyl) diphenol (AdDP) over five generations using a Nematode Growth Medium (NGM) 1.7% agar plate. In the fourth generation, the phenols affected the fecundity rate of C. elegans at doses 100- to 10000-fold lower than the LC50s. In particular, at 1 nM BisA, the number of worms decreased significantly to about 50% of control (p < 0.05). A comparison of the number of viable worms and eggs suggested that the phenols exert hatching toxicity. In addition, individuals with an abnormality in the vulva, which could not ovulate, appeared on the phenol-containing plates. We confirmed that phenols disrupt reproduction in C. elegans and that the method using NGM agar plates facilitates multi-generational toxicity tests of chemicals that are poorly soluble in water

Caenorhabditis elegans Responses to Specific Steroid Hormones

In this paper, Caenorhabditis elegans (C. elegans) is proposed as a model organism for studying chemical effects over multiple generations. We investigated whether C. elegans responds to vertebrate steroid hormones. We found that estrogenic steroids, especially estradiol (E2), have a cholesterol-like potency in supporting the reproduction of C. elegans. In contrast, testosterone (TS) and diethylstilbestrol (DES) did not display this potency. On the other hand, E2, TS and DES supressed the fecundity rate of C. elegans, when culture carried out with cholesterol. Moreover effect of TS accumulated over generation, in contrast to the other chemicals tested. These data suggested that with convenient biomarkers such as fecundity, C. elegans might be an effective model organism for studying chemical actions, including the disruption of reproduction