Abstract

Annals of Environmental Science
Volume 1, September 2007, Pages 81-90
www.aes.northeastern.edu, ISSN 1939-2621

Dissolved Humic Substances Facilitate Fish Life in Extreme Aquatic Environments and Have the Potential to Extend the Lifespan of Caenorhabditis Elegans

C.E.W. Steinberg, N. Saul, K. Pietsch, T. Meinelt, S. Rienau and R. Menzel, Laboratory of Freshwater and Stress Ecology, Institute of Biology, Humboldt University at Berlin, and Leibniz Institute of Freshwater Ecology and Inland Fisheries, Department of Inland Fisheries, Berlin, Germany

Received April 17, 2007; in final form August 14, 2007; Accepted August 24, 2007

Dissolved humic substances (HSs) are taken up by organisms and interact on various molecular and biochemical levels. With two examples, we show that HSs facilitate fish life in low pH and low calcium waters and promote longevity by mild chemical stress. We re-visit recent papers on fish adaptation in the Amazonian Rio Negro and re-interpret the results on the basis of the recent finding of gene control in the nematode Caenorhabditis Elegans. In the nematode, several genes are up-regulated. This may also account for the maintenance of fish life in the Rio Negro. Exposure to HSs exerts mild chemical stress on the exposed organisms and deprives them of energy; however, the nematode C. elegans actively looks for such environments. With life-table and DNA gene filter studies we show that HSs may cause longevity and multiple stress resistance. Furthermore, we propose likely structures of the HSs responsible for these effects.