Ralph Menzel et al. (2008) European Worm Meeting "Humic material induces behavioral and transcriptional responses in the nematode Caenorhabditis elegans and extends its lifespan"

Kerstin Pietsch, Heike Staudacher, Stefanie Rienau, Ralph Menzel, Christian E W Steinberg, Nadine Saul, Waltraud Wild

[European Worm Meeting, 2008]

Humic substances (HS) are complex organic molecules constituting the most. abundant source of natural organic matter (NOM) in freshwater and soil. ecosystems. They are taken up by organisms and interact on various. molecular and biochemical levels. Recent advances have identified that they. interfere with biological systems, via the induction of biotransformation. enzymes and the production of internal oxidative stress.. The nematode model organism Caenorhabditis elegans was chosen to. investigate whether natural and synthetic HS induce (i) a behavioral. attraction, (ii) the reproduction, (iii) an increased lifespan, and (iv) a. response in transcriptional expression. The phenomenological attractant. experiments provided evidence that HS attract the worm and exert distinct. chemical cues. In the reproduction assay, only the highest concentration. (30 mg/L dissolved organic carbon) resulted in a slight decrease in brood. size, highlighting an overall intrinsic tolerance towards humic material.. Lifespan experiments showed that at least one HS increases the lifespan of. Caenorhabditis elegans. Finally, DNA array experiments were performed from. control and HS treated worms. Significant transcriptional changes. (exceeding a two-fold in- or decrease) were identified and in chemosensors,. olfactory receptors, as well as enzymes of the biotransformation system. (glutathione S-transferases, short-chain dehydrogenases) and. vitellogenines. The results were proved by quantitative real-time RT-PCR,. thereby confirming that humic material is recognized as an environmental. signaling chemical.