Feeding is inhibited by sublethal concentrations of toxicants and by heat stress in the nematodeCaenorhabditis elegans: Relationship to the cellular stress response

Jones, Donald; Candido, E. Peter M.

doi:10.1002/(sici)1097-010x(19990701)284:2<147::aid-jez4>3.0.co;2-z

Cited by 116 publications

(16 citation statements)

References 41 publications

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“…This supports the results of previous DEBtox analysis of Cd effect in C. elegans [33,34], as well as the results of similarly designed studies of Cd toxicity for the springtail Folsomia candida [18], and Daphnia magna [35]. An effect of Cd on energy acquisition in C. elegans is also consistent with the observation of reduced feeding following Cd exposure [36,37]. …”

Section: Discussionsupporting

confidence: 88%

Linking toxicant physiological mode of action with induced gene expression changes in Caenorhabditis elegans

et al. 2010

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BackgroundPhysiologically based modelling using DEBtox (dynamic energy budget in toxicology) and transcriptional profiling were used in Caenorhabditis elegans to identify how physiological modes of action, as indicated by effects on system level resource allocation were associated with changes in gene expression following exposure to three toxic chemicals: cadmium, fluoranthene (FA) and atrazine (AZ).ResultsFor Cd, the physiological mode of action as indicated by DEBtox model fitting was an effect on energy assimilation from food, suggesting that the transcriptional response to exposure should be dominated by changes in the expression of transcripts associated with energy metabolism and the mitochondria. While evidence for effect on genes associated with energy production were seen, an ontological analysis also indicated an effect of Cd exposure on DNA integrity and transcriptional activity. DEBtox modelling showed an effect of FA on costs for growth and reproduction (i.e. for production of new and differentiated biomass). The microarray analysis supported this effect, showing an effect of FA on protein integrity and turnover that would be expected to have consequences for rates of somatic growth. For AZ, the physiological mode of action predicted by DEBtox was increased cost for maintenance. The transcriptional analysis demonstrated that this increase resulted from effects on DNA integrity as indicated by changes in the expression of genes chromosomal repair.ConclusionsOur results have established that outputs from process based models and transcriptomics analyses can help to link mechanisms of action of toxic chemicals with resulting demographic effects. Such complimentary analyses can assist in the categorisation of chemicals for risk assessment purposes.

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Section: Discussionsupporting

confidence: 88%

Linking toxicant physiological mode of action with induced gene expression changes in Caenorhabditis elegans

et al. 2010

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“…Many published studies on metal toxicity in C. elegans have measured sublethal endpoints such as reproduction, lifespan, motility and feeding inhibition (e.g. Jones and Candido 1999; Swain et al 2004; Anderson et al 2001), but none of them covers all the metals tested here, and therefore these endpoints are not further explored or discussed.…”

Section: Resultsmentioning

confidence: 99%

“…With suitable modifications such as centrifugal extraction of soil pore water (Power and de Pomerai 1999), other endpoints including feeding inhibition (Jones and Candido 1999) can also be tested. These provide an overview of how soil-dwelling biota (including free-living nematodes such as C. elegans ) respond to the prevailing soil conditions—for instance metal and/or pesticide contamination.…”

Section: Introductionmentioning

confidence: 99%

Transgenic nematodes as biosensors for metal stress in soil pore water samples

et al. 2011

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Caenorhabditis elegans strains carrying stress-reporter green fluorescent protein transgenes were used to explore patterns of response to metals. Multiple stress pathways were induced at high doses by most metals tested, including members of the heat shock, oxidative stress, metallothionein (mtl) and xenobiotic response gene families. A mathematical model (to be published separately) of the gene regulatory circuit controlling mtl production predicted that chemically similar divalent metals (classic inducers) should show additive effects on mtl gene induction, whereas chemically dissimilar metals should show interference. These predictions were verified experimentally; thus cadmium and mercury showed additive effects, whereas ferric iron (a weak inducer) significantly reduced the effect of mercury. We applied a similar battery of tests to diluted samples of soil pore water extracted centrifugally after mixing 20% w/w ultrapure water with air-dried soil from an abandoned lead/zinc mine in the Murcia region of Spain. In addition, metal contents of both soil and soil pore water were determined by ICP-MS, and simplified mixtures of soluble metal salts were tested at equivalent final concentrations. The effects of extracted soil pore water (after tenfold dilution) were closely mimicked by mixtures of its principal component ions, and even by the single most prevalent contaminant (zinc) alone, though other metals modulated its effects both positively and negatively. In general, mixtures containing similar (divalent) metal ions exhibited mainly additive effects, whereas admixture of dissimilar (e.g. trivalent) ions often resulted in interference, reducing overall levels of stress-gene induction. These findings were also consistent with model predictions.Electronic supplementary materialThe online version of this article (doi:10.1007/s10646-011-0804-0) contains supplementary material, which is available to authorized users.

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“…Two toxins were tested. Phenethyl isothiocyanate (PEITC), a naturally occurring nematicide [51] which is being considered as a replacement for synthetic controls [52], and methanol, which is occasionally applied in soil remediation [53] and is known to affect nematode feeding activity [22, 54]. Chemicals were added to the samples by pipetting them onto the water surface without disturbing the Ludox® TMA/water column.…”

Section: Methodsmentioning

confidence: 99%

“…As solvents were not used in this study, a dosage at the upper end of this range was chosen by adding 10 µL of PEITC (Sigma, 99%, 253,731). Methanol (Fisher, M/4056/17) was added at 0.5 mL, which is the dose predicted to result in 100% lethality of C. elegans [54]. As an oil, PEITC formed an emulsion visible as a thin film from which compounds were allowed to diffuse, while methanol dissolved (Fig.…”

Section: Methodsmentioning

confidence: 99%

Dynamic biospeckle analysis, a new tool for the fast screening of plant nematicide selectivity

et al. 2019

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BackgroundPlant feeding, free-living nematodes cause extensive damage to plant roots by direct feeding and, in the case of some trichodorid and longidorid species, through the transmission of viruses. Developing more environmentally friendly, target-specific nematicides is currently impeded by slow and laborious methods of toxicity testing. Here, we developed a bioactivity assay based on the dynamics of light ‘speckle’ generated by living cells and we demonstrate its application by assessing chemicals’ toxicity to different nematode trophic groups.ResultsFree-living nematode populations extracted from soil were exposed to methanol and phenyl isothiocyanate (PEITC). Biospeckle analysis revealed differing behavioural responses as a function of nematode feeding groups. Trichodorus nematodes were less sensitive than were bacterial feeding nematodes or non-trichodorid plant feeding nematodes. Following 24 h of exposure to PEITC, bioactivity significantly decreased for plant and bacterial feeders but not for Trichodorus nematodes. Decreases in movement for plant and bacterial feeders in the presence of PEITC also led to measurable changes to the morphology of biospeckle patterns.ConclusionsBiospeckle analysis can be used to accelerate the screening of nematode bioactivity, thereby providing a fast way of testing the specificity of potential nematicidal compounds. With nematodes’ distinctive movement and activity levels being visible in the biospeckle pattern, the technique has potential to screen the behavioural responses of diverse trophic nematode communities. The method discriminates both behavioural responses, morphological traits and activity levels and hence could be used to assess the specificity of nematicidal compounds.

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Feeding is inhibited by sublethal concentrations of toxicants and by heat stress in the nematodeCaenorhabditis elegans: Relationship to the cellular stress response

Cited by 116 publications

References 41 publications

Linking toxicant physiological mode of action with induced gene expression changes in Caenorhabditis elegans

Linking toxicant physiological mode of action with induced gene expression changes in Caenorhabditis elegans

Transgenic nematodes as biosensors for metal stress in soil pore water samples

Dynamic biospeckle analysis, a new tool for the fast screening of plant nematicide selectivity

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