Requirements of non‐heme iron and heme iron in the nematode, Caenorhabditis elegans

Abstract

A basal medium was prepared with both non‐heme iron and heme iron eliminated from C. elegans Maintaince Medium. After being pre‐cultured in this medium, C. elegans were inoculated into a 3×5 factorial design of experimental media, consisting of 5 levels of non‐heme iron (0, 0.0672, 0.336, 8.40, 210 μg/ml) and 3 levels of cyt c (0, 50.0, 500 μg/ml). The population growth was counted at the 28th Day, and iron uptake and % iron absorption of nematodes were analyzed by Atomic Absorption Spectrophotometry. At 0 μg/ml iron and 0 μg/ml cyt c, the population growth was very poor. At 0 μg/ml cyt c, as iron level increased to 8.40 μg/ml, the nematode population increased to 5.98±0.53×103 Nema/ml. As iron concentration further increased, significant declines in nematode population were observed, indicating iron toxicity. At 0 μg/ml iron, as cyt c level increased, the population growth was greatly increased. The highest population growth was achieved at 8.40 μg/ml iron and 500 μg/ml cyt c, suggesting an additive requirement of non‐heme and heme iron. The iron uptake increased when either non‐heme or heme iron levels increased in the media. At 0 μg/ml cyt c, the % iron absorption decreased with the increase of iron level in the media. This findings was in accordance with the “mucosal block” theory. At 50.0 and 500 μg/ml cyt c, the % iron absorption greatly increased, suggesting heme iron greatly enhanced non‐heme iron absorption in C. elegans.