Effects-based Assays in the Earthworm Aporrectodea caliginosa: Their Utilisation for Evaluation of Contaminated Sites before and after Remediation (8 pp)     

Lynn?BoothEmail author  Vanessa?Heppelthwaite  Kathryn?O’Halloran 《Journal of Soils and Sediments》2005,5(2):87-94

Goal, Scope and Background   In a preliminary ecological risk assessment, potential adverse effects of contaminants are often evaluated by measuring chemical residues and comparing these with regulatory guidelines. However limitations with this approach with regards to establishing actual effects have resulted in the increasing usage of sublethal effects-based assays, including biomarkers, to evaluate the hazard posed by contaminants in the environment. In this study a number of effects-based endpoints in the earthworm Aporrectodea caliginosa were evaluated to determine their comparative sensitivity for assessment of adverse effects of soil contaminated with petroleum hydrocarbons. Methods   Adult and juvenile earthworms were exposed for 4 weeks to sublethal concentrations of soil collected before and after remediation of a petroleum-contaminated site. A suite of endpoints were measured in these earthworms, including mortality, fecundity, growth, and juvenile maturation, and two less traditional endpoints, the biomarker, the neutral red retention assay (NRRA) and an avoidance behaviour test. Results and Discussion   Cocoon viability in this species is not a reliable parameter to measure, due to low viability in controls and a high coefficient of variation. Growth in adult earthworms was a more sensitive parameter than cocoon production. Maturation and growth of juveniles have been proposed as more sensitive endpoints than adult cocoon production and growth respectively. This was not apparent in the growth parameters, but maturation of juveniles did appear to be more sensitive than cocoon production by adults. The NRRA was a more sensitive parameter than cocoon production, and the NRRA and growth were both affected at the lowest concentration tested. The NRRA response appeared to be more sensitive than growth, but NRRT was only evaluated in one soil only, while the other parameters were assessed in two soils. However, the NRRA has previously been found to be more sensitive than growth after exposure to a number of contaminants. The avoidance behaviour assay exhibited similar sensitivity to growth and fecundity and could therefore be useful as a simple pre-screening test. Conclusion   The chronic endpoints, growth, cocoon production, and juvenile maturation parameters, were all sensitive endpoints for detecting exposure to the petroleum-hydrocarbon-contaminated soil. The NRRA was the most sensitive of the endpoints assessed and could be used as an early-warning indicator to predict adverse impacts. Avoidance behaviour could be used as a simple pre-screening test to evaluate contaminated soils prior to more extensive and invasive testing. Recommendations and Perspective   Measuring chemical concentrations in environmental samples is not always useful, as the toxicological impacts of exposure to these concentrations are not always discernible. However, the use of effects-based endpoints, either in situ or in the laboratory using laboratory-reared earthworms, can account for the bioavailability of chemicals in the soil, and can therefore provide information on the toxicological impacts of exposure. The assays tested in this research were sensitive indicators of exposure, and therefore can be used to determine potential ecological risks at contaminated sites and to monitor the progress of remediation at these sites.  相似文献   

Impact of selective logging on genetic composition and demographic structure of four tropical tree species     

B. Degen  L. Blanc  L. Maggia  S. Gourlet-Fleury 《Biological conservation》2006,131(3):386-401

Over-exploitation and fragmentation are serious problems for tropical forests. Most sustainable forest management practices avoid clear-cuts and apply selective logging systems focused on a few commercial species. We applied a simulation model to estimate the impact of such selective logging scenarios on the genetic diversity and demography of four tropical tree species from French Guiana. The simulations used data on genetic and demographic composition, growth, phenology and pollen and seed dispersal obtained for Dicorynia guianensis, Sextonia rubra, Symphonia globulifera and Vouacapoua americana at the experimental site in Paracou. Whereas Symphonia globulifera serves as a model for a species with low logging pressure, the other three species represent the most exploited tree species in French Guiana. In simulations with moderate logging, typical for French Guiana, with large cutting diameter (>60 cm diameter) and long cutting cycles (65 years), the two species V. americana and Sextonia rubra were not able to recover their initial stock at the end of the rotation period, with a large decrease in the number of individuals and in basal area. Under a more intensive logging system (cutting diameter >45 cm diameter, cutting cycles of 30 years) that is common practice in the Brazilian Amazon, only Symphonia globulifera showed no negative impact. Generally, the differences between the genetic parameters in the control scenarios without logging and the logging scenarios were surprisingly small. The main reasons for this were the overlapping of generations and the effective dispersal ability of gene vectors in all species, which guarantee relative homogeneity of the genetic structure in different age classes. Nevertheless, decreasing the population size by logging reduced the number of genotypes and caused higher genetic distances between the original population and the population at the end of the logging cycles. Sensitivity analysis showed that genetic changes in the logging scenarios were principally determined by the growth, densities and cutting diameter of each species, and only to a very small extent by the reproductive system including factors such as pollen and seed dispersal and flowering phenology.  相似文献   

Rapid changes in throughput from single motor cortex neurons to muscle activity     

Davidson AG  Chan V  O'Dell R  Schieber MH 《Science (New York, N.Y.)》2007,318(5858):1934-1937

Motor cortex output is capable of considerable reorganization, which involves modulation of excitability within the cortex. Does such reorganization also involve changes beyond the cortex, at the level of throughput from single motor cortex neurons to muscle activity? We examined such throughput during a paradigm that provided incentive for enhancing functional connectivity from motor cortex neurons to muscles. Short-latency throughput from a recorded neuron to muscle activity not present during some behavioral epochs often appeared during others. Such changes in throughput could not always be attributed to a higher neuron firing rate, to more ongoing muscle activity, or to neuronal synchronization, indicating that reorganization of motor cortex output may involve rapid changes in functional connectivity from single motor cortex neurons to alpha-motoneuron pools.  相似文献   

Development of biomarkers inAporrectodea caliginosa andLumbricus rubellus for detecting exposure to benzo[a]pyrene     

Lynn H. Booth  Vanessa J. Heppelthwaite  Kathryn O’Halloran 《Journal of Soils and Sediments》2002,2(3):148-154

Objectives and Methods. The sensitivity of two biomarkers, the neutral red retention assay (NRRA) and cytochrome P450 were evaluated in the earthwormAporrectodea caliginosa for their potential to detect exposure to benzo[a]pyrene (BaP). Cytochrome P450 was also evaluated in the earthwormLumbricus rubellus, and measured using the substrate ethoxycoumarin. Optimal assay conditions (pH, and temperature) were determined, followed by exposure of earthworms to 20 mg/kg BaP (a typical concentration at contaminated sites in New Zealand). Ethoxycoumarin-O-dealkylase (ECOD) activity was measured after 7, 14, and 21 days exposure. The NRRA was evaluated in earthworms exposed to 0.2, 20, and 100 mg BaP/kg, and biomarker responses were compared with effects on body weight. Results and Discussion Benzo[a]pyrene failed to induce ECOD activity in either earthworm species, and therefore it is not useful as a biomarker of BaP exposure and was not evaluated further. In all cases, the NRRA was significantly affected in the absence of any effects on earthworm body weight, indicating that this assay can detect exposure to BaP at a range of concentrations comparable to those found at contaminated sites. The NRRA should be linked to reproductive endpoints, then it can be used as an early warning indicator of adverse effects. Establishing biomarker stability under environmental conditions is an important step in biomarker development. Therefore, the effects of soil type (sandy soil, silt loam, and a clay soil), moisture content (15–30%), and temperature (5–20°) on the NRRA were determined. In all cases, there was no effect on the NRRA, indicating that this assay is very stable under varying environmental conditions. Conclusion and Outlook In conclusion, cytochrome P450 activity does not appear to be a useful indicator of PAH exposure in eitherA. caliginosa or L.rubellus, and due to the inherently low activity, it is not suitable as a routine biomarker for detecting environmental contamination by these compounds. In contrast, the NRRA in the earthworm A.caliginosa is a promising indicator of PAH exposure at the concentrations likely to be found in contaminated sites in New Zealand, and therefore has potential for evaluating these contaminated sites. If the NRRA can be linked to ecologically important life-cycle endpoints, such as reproduction, then it could be used as an early warning indicator of adverse effects at contaminated sites, i.e., by measuring biomarker responses in earthworms from a ‘contaminated area’ and comparing these with earthworms from a matched control area.  相似文献   

Errors in repeated measurements of soil water content in pots using a ThetaProbe     

L. Blanc  J.McP. Dick 《Soil Use and Management》2003,19(1):87-88

Abstract. The accuracy of a ThetaProbe (Delta-T Devices Ltd, UK) to obtain repeated measures of soil water content in pot plants was tested. This alternative to balance determinations led to a large underestimation of water content, varying from 12.2 to 21.8% of the total water content, depending on soil type.  相似文献   

Supply of fresh sea fish in Tananarive. Study of some laboratory tests complementary to organoleptic evaluation     

F Blanc  J Blancou 《Revue d'élevage et de médecine vétérinaire des pays tropicaux》1971,24(4):587-595

  相似文献   

Isolation and identification of goose parvovirus in the UK   总被引：2，自引：0，他引：2  

Gough D  Ceeraz V  Cox B  Palya V  Mato T 《The Veterinary record》2005,156(13):424

  相似文献   

Note on the bacterial contamination of shrimps fished in Madagascar     

J Blancou  F Blanc 《Revue d'élevage et de médecine vétérinaire des pays tropicaux》1971,24(2):233-238

  相似文献   

Activity of spinosad on stored-tobacco insects and persistence on cured tobacco stripst     

Blanc MP  Panighini C  Gadani F  Rossi L 《Pest management science》2004,60(11):1091-1098

Every year raw tobacco and manufactured tobacco products are lost to two major storage pests, the cigarette beetle, Lasioderma serricorne (F) and the tobacco moth, Ephestia elutella (Hiibner). Post-harvest management of both insects is achieved through sanitation, insect monitoring and fumigation with phosphine. However, insect resistance to phosphine and control failures have been reported, and fumigants are under constant regulatory pressure. Here we report the evaluation of spinosad, a bioinsecticide derived from the fermentation of the soil micro-organism Saccharopolyspora spinosa Mertz & Yao. Spinosad was first registered in 1997 and is now widely used as a field pest control agent on many crops, including tobacco. The insecticidal activity of the fermentation product (technical spinosad, TS) was measured by diet incorporation assays against L serricorne and E elutella larvae. Mortality levels were determined on newly hatched larvae and over the whole insect life cycle. For both species, no emergence of adult insects was observed in cured tobacco sprayed with 50mg TS kg(-1) and inoculated with eggs or newly hatched larvae. These results indicated that spinosad has potential for the control of both species in stored tobacco, since 100% control of both pests could be achieved at 50 mg TS kg(-1), and with almost full control (90-95%) at 10 mg kg(-1). We also monitored the stability of the product on cured tobacco. The original concentration of the main active component of TS, spinosyn A, did not change significantly over 18 months, indicating no loss of spinosad during a typical leaf storage period of time. Bioassays against larvae confirmed that the bioinsecticidal activity of spinosad was retained.  相似文献   

Changes in glucosinolate concentrations, myrosinase activity, and production of metabolites of glucosinolates in cabbage (Brassica oleracea Var. capitata) cooked for different durations     

Rungapamestry V  Duncan AJ  Fuller Z  Ratcliffe B 《Journal of agricultural and food chemistry》2006,54(20):7628-7634

In cabbage, glucosinolates such as sinigrin are hydrolyzed by plant myrosinase to allyl isothiocyanate (AITC), allyl cyanide, and, in the presence of an epithiospecifier protein, 1-cyano-2,3-epithiopropane (CEP). Isothiocyanates have been implicated in the cancer-protective effects of Brassica vegetables. The effect of processing on the hydrolysis of glucosinolates was investigated in cabbage. Cabbage was steamed or microwaved for six time durations over 7 min. Glucosinolate concentrations were slightly reduced after microwave cooking (P < 0.001) but were not influenced after steaming (P < 0.05). Myrosinase activity was effectively lost after 2 min of microwave cooking and after 7 min of steaming. Hydrolysis of residual glucosinolates following cooking yielded predominantly CEP at short cooking durations and AITC at longer durations until myrosinase activity was lost. Lightly cooked cabbage produced the highest yield of AITC on hydrolysis in vitro, suggesting that cooking Brassica vegetables for a relatively short duration may be desirable from a health perspective.  相似文献