Humic Material Induces Behavioral and Global Transcriptional Responses in the Nematode <i>Caenorhabditis elegans</i>

Menzel, Ralph; Stürzenbaum, Stephen R.; Bärenwaldt, Anne; Kulas, Jana; Steinberg, Christian E. W.

doi:10.1021/es050884s

Cited by 70 publications

(51 citation statements)

References 51 publications

(56 reference statements)

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“…Consequently, it is assumed that the SOM itself acted as natural xenobiotics in relation to their interactions with the biota-in analogy to secondary plant compounds (Li et al 2007); yet, in contrast to the latter, HSs are not synthesized to defend against herbivory, but challenge any exposed organism (Timofeyev et al 2004(Timofeyev et al , 2006Menzel et al 2005b;Bedulina et al 2010). Indeed, HSs as the major part of P have a variety of functional groups, which resemble xenobiotic chemicals.…”

Section: Resultsmentioning

confidence: 99%

Organic carbon source in formulated sediments influences life traits and gene expression of Caenorhabditis elegans

et al. 2011

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River water quality is strongly influenced by their sediments and their associated pollutants. To assess the toxic potential of sediments, sediment toxicity tests require reliable control sediments, potentially including formulated control sediments as one major option. Although some standardization has been carried out, one critical issue still remains the quality of sediment organic matter (SOM). Organic carbon not only binds hydrophobic contaminants, but may be a source of mild toxicity, even if the SOM is essentially uncontaminated. We tested two different sources of organic carbon and the mixture of both (Sphagnum peat (P) and one commercial humic substances preparation-HuminFeed(®), HF) in terms of life trait variables and expression profiles of selected life performance and stress genes of the nematode Caenorhabditis elegans. In synchronous cultures, gene expression profiling was done after 6 and 48 h, respectively. The uncontaminated Sphagnum P reduced growth, but increased numbers of offspring, whereas HF did not significantly alter life trait variables. The 6 h expression profile showed most of the studied stress genes repressed, except for slight to strong induction in cyp-35B1 (all exposures), gst-38 (only mixture), and small hsp-16 genes (all exposures). After 48 h, the expression of almost all studied genes increased, particularly genes coding for antioxidative defense, multiple xenobiotic resistance, vitellogenin-like proteins, and genes regulating lifespan. Overall, even essentially uncontaminated SOM may induce several modes of action on the molecular level in C. elegans which may lead to false results if testing synthetic xenobiotics. This contribution is a plea for a strict standardization of the SOM quality in formulated sediments and to check for corresponding effects in other model sediment organisms, especially if using molecular toxicity endpoints.

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Section: Resultsmentioning

confidence: 99%

Organic carbon source in formulated sediments influences life traits and gene expression of Caenorhabditis elegans

et al. 2011

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“…Attraction assay NGM agar plates (92 mm) were prepared, in accordance to Menzel et al (2005), with six alternating spots of bacteria, lacking or supplemented with PPs (Q 200 lM, CA 300 lM, RA 200 lM). One L4 juvenile F1 worm was placed on each of the six spots and, following incubation for 72 h at 20°C, the number of F2 offspring on each individual spot determined.…”

Section: Growth Alterationsmentioning

confidence: 99%

Hormetins, antioxidants and prooxidants: defining quercetin-, caffeic acid- and rosmarinic acid-mediated life extension in C. elegans

et al. 2011

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Quercetin, Caffeic- and Rosmarinic acid exposure extend lifespan in Caenorhabditis elegans. This comparative study uncovers basic common and contrasting underlying mechanisms: For all three compounds, life extension was characterized by hormetic dose response curves, but hsp-level expression was variable. Quercetin and Rosmarinic acid both suppressed bacterial growth; however, antibacterial properties were not the dominant reason for life extension. Exposure to Quercetin, Caffeic- and Rosmarinic acid resulted in reduced body size, altered lipid-metabolism and a tendency towards a delay in reproductive timing; however the total number of offspring was not affected. An indirect dietary restriction effect, provoked by either chemo-repulsion or diminished pharyngeal pumping was rejected. Quercetin and Caffeic acid were shown to increase the antioxidative capacity in vivo and, by means of a lipofuscin assay, reduce the oxidative damage in the nematodes. Finally, it was possible to demonstrate that the life and thermotolerance enhancing properties of Caffeic- and Rosmarinic acid both rely on osr-1, sek-1, sir-2.1 and unc-43 plus daf-16 in the case of Caffeic acid. Taken together, hormesis, in vivo antioxidative/prooxidative properties, modulation of genetic players, as well as the re-allocation of energy all contribute (to some extent and dependent on the polyphenol) to life extension.

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“…Such responses have, moreover, been linked to specific genes and pathways. Under field conditions abiotic stress is, however, seldom uni-dimensional, thus the task of defining transcriptional norms and deciphering molecular genetic response pathways is considerably more challenging (Steinberg et al 2008), although not impossible as demonstrated by studies on humic substances (Menzel et al 2005) and river sediment mixture toxicity .…”

Section: Transcriptional Reaction Norms and Abiotic Stress Within A Gmentioning

confidence: 99%

The significance of genome-wide transcriptional regulation in the evolution of stress tolerance

Roelofs¹,

Morgan

Stürzenbaum

2010

Evol Ecol

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It is widely recognized that stress plays an important role in directing the adaptive adjustment of an organism to changing environments. However, very little is known about the evolution of mechanisms that promote stress-induced variation. Adaptive transcriptional responses have been implicated in the evolution of tolerance to natural and anthropogenic stressors in the environment. Recent technological advances in transcriptomics provide a mechanistic understanding of biological pathways or processes involved in stress-induced phenotypic change. Furthermore, these studies are (semi) quantitative and provide insight into the reaction norms of identified target genes in response to specific stressors. We argue that plasticity in gene expression reaction norms may be important in the evolution of stress tolerance and adaptation to environmental stress. This review highlights the consequences of transcriptional plasticity of stress responses within a single generation and concludes that gene promoters containing a TATA box are more capable of rapid and variable responses than TATA-less genes. In addition, the consequences of plastic transcriptional responses to stress over multiple generations are discussed. Based on examples from the literature, we show that constitutive over expression of specific stress response genes results in stress adapted phenotypes. However, organisms with an innate capacity to buffer stress display plastic transcriptional responses. Finally, we call for an improved integration of the concept of phenotypic plasticity with studies that focus on the regulation of transcription.

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Humic Material Induces Behavioral and Global Transcriptional Responses in the Nematode Caenorhabditis elegans

Cited by 70 publications

References 51 publications

Organic carbon source in formulated sediments influences life traits and gene expression of Caenorhabditis elegans

Organic carbon source in formulated sediments influences life traits and gene expression of Caenorhabditis elegans

Hormetins, antioxidants and prooxidants: defining quercetin-, caffeic acid- and rosmarinic acid-mediated life extension in C. elegans

The significance of genome-wide transcriptional regulation in the evolution of stress tolerance

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