Download Procedures for Reproductive Risk Evaluation Based on Diagnostic

DEPARTMENT for ENVIRONMENT, FOOD and RURAL AFFAIRS
Research and Development
CSG 15
Final Project Report
(Not to be used for LINK projects)
Two hard copies of this form should be returned to:
Research Policy and International Division, Final Reports Unit
DEFRA, Area 301
Cromwell House, Dean Stanley Street, London, SW1P 3JH.
An electronic version should be e-mailed to [email protected]
Project title
Procedures for Reproductive Risk Evaluation Based on Diagnostic and
Innovative Cellular Tools (Predict)
DEFRA project code
AE1118
Contractor organisation
and location
Plymouth Marine Laboratory
Total DEFRA project costs
Project start date
£ 24,6215
01/10/97
Project end date
01/04/01
Executive summary (maximum 2 sides A4)
Executive Summary
Assessing the harmful impact of chemical contaminants on the health of the coastal marine
environment is part of MAFF’s remit; and is a major scientific and conceptual challenge in the light of
the comprehensive list of chemicals identified by OSPAR as potentially problematical (OSPAR
Strategy with regard to Hazardous Substances; Ref No. 1998-16). The major aim of this proposal
was to examine the effects of contaminant chemicals on the developing and free eggs from marine
mussels in order to provide reliable and simple diagnostic tests of harmful effect that are predictive of
reduced egg viability, i.e. as an indicator of detriment. In addition, since eggs reside in the plankton
for several weeks, during which time they are likely to be exposed to organic chemical contaminants
(xenobiotics) and UVB radiation, the impact of these two stressing factors and their interactions was
assessed on the biota. The predictive capability of diagnostic tools for selected endpoints such as
cellular and physiological pathology of eggs and larvae was also evaluated and modelled in relation
to the physical characteristics of the pollutant chemicals (Quantitiative Strucure Activity Relationships,
QSARs). Methods used included lysosomal stability (neutral red retention), which is now
internationally recognised as an indicator of health status of the individual animal. Other methods
were the multidrug resistance membrane transporter system ( an indicator of contaminant exposure),
and larval development bioassays.
The project objectives were modified and refocused during the course of the investigation, in
agreement with the Project Officer. The overall thrust of the research in the original proposal was
directed towards the study of contaminant effect on eggs whereas the research undertaken has been
CSG 15 (Rev. 6/02)
1
Project
title
Procedures for Reproductive Risk Evaluation Based on
Diagnostic and Innovative Cellular Tools (Predict)
DEFRA
project code
AE1118
greatly extended to consider impacts on both eggs and early life stages. In addition, the original
programme of research on UVB radiation effects was restricted to eggs and larvae of invertebrates
whereas, and as a result of collaborative research with CEFAS, this area of work was greatly
extended to include larval stages of both invertebrates and fish. These changes in focus have
represented a considerable increase in research effort which has had consequences for other areas
of work, notably the field work which was restricted to a single population, within the programme.
Despite living in contaminated environments, some invertebrates can successfully reproduce,
develop and grow. It is this ability to tolerate cocktails of contaminants that has lead researchers to
conclude that certain marine invertebrates possess defence mechanisms against chemical insult. A
mechanism similar to mammalian cell multidrug resistance (MDR) has been reported in aquatic
organisms including the embryonic stages. Recent studies have shown that this MDR phenotype, or
component of it, is part of a highly conserved system among the various phyla. Cells exhibiting the
MDR phenotype generally show a decreased intracellular drug accumulation and a lack of
responsiveness to a variety of natural and synthetic toxic compounds. Inhibitors of the MDR system,
such as such as the drug verapamil (MDR-associated ATPase inhibitor), can circumvent this
resistance. Accumulation of fluorescent MDR transportable dyes such as rhodamine-B have been
measured and shown to be verapamil- sensitive.
Larval stages of mussels have been successfully deployed for environmental impact assessments in
support of cellular and physiological biomarkers and this study has demonstrated the presence of the
MDR transporter system in the early life stages of mussels.
Spawning of many commercially important fish and shellfish occurs in coastal waters, where larval
stages reside in the upper water column, with the potential risk of exposure to anthropogenic
contaminants and UV-B radiation. Their relative inactivity and absence of thick protective shells or
scales enhance their vulnerability to radiation. This highlights the potential threat of increasing levels
of UV-B for commercial fisheries and the aquaculture industry in temperate regions.
Quantitative structure-activity relationship (QSAR) studies on six chemicals, including 5
environmental contaminants, showed that toxicity was significantly correlated with molar refractivity,
an indicator of interaction with biological molecules. Weaker trends were observed for lipid solubility,
molecular area and molecular volume. The behaviour of all of the contaminants was predicted by a
QSAR-based model/data support system.
N.B- Please see Technical Report for further information
CSG 15 (Rev. 6/02)
2
Project
title
Procedures for Reproductive Risk Evaluation Based on
Diagnostic and Innovative Cellular Tools (Predict)
DEFRA
project code
Scientific report (maximum 20 sides A4)
CSG 15 (Rev. 6/02)
3
AE1118