104
M.S. Clark et al.
being specifically targeted to the problems associated with climate change and their
effects on functional biodiversity.
3.4.4.3 Ecotoxicology Monitoring
Marine ecosystems, particularly coasts, estuaries and coral reefs, are currently
experiencing major crises worldwide as environmental change places significant
physiological stress (metals, pesticides, chemicals but also parasites) on organisms.
Understanding ecosystem resilience and predicting the impact of such environmental stresses on marine organisms depends on knowing the physiological status
and plasticity of these organisms in these ecosystems. Traditional ecotoxicology
in marine species involves the study of “biological biomarkers” such as enzyme
activities and stress protein quantification, immunological parameters evaluation
and life trait (growth, reproductive stage) evaluation. Recent progresses in genomic
and proteomic techniques have lead to the emergence of new approaches in ecotoxicology called “ecotoxicogenomics”. This is defined as the study of gene and protein
expression in non-model organisms that is important in understanding responses to
environmental toxicant exposures. Ecotoxicogenomics is a technology that has been
made possible mainly by the advent of DNA microarray analyses. Microarrays have
aided our understanding of relationships between global gene expression profiles,
physiological states of an organism, and traditional toxic endpoints (Irwin et al.
2004, Lee et al. 2003).
Genomics provides a detailed view of physiological diversity and function, and
thus a mechanistic insight into how organisms respond to environmental stress.
Genomic approaches in ecotoxicology will:
• Improve our understanding of toxicant/stress/infection mechanisms.
• Develop a physiological perspective on the environmental facilitation of toxicant/stress/infection within organisms
• Produce tools to predict the spread of toxicant/stress/infection, leading to better
assessment and prediction of environmental health.
In particular, the application of ecotoxicogenomics will extrapolate from experimental in vitro to in vivo systems and across the species barrier. It will aid in the
understanding of specific molecular events underlying the mode of action of toxicants, and therefore these can be developed as biomarkers to identify exposure to
environmental stressors.
Gene expression profiling can be used to show that the specific genes repressed
or induced upon exposure to a toxic stress vary depending on the cell type and the
type of toxicants to which the cells were exposed (Troester et al. 2004). The major
challenge of ecotoxicogenomic approaches will be to take into account intrinsic
sources of variability in gene expression levels due to different physiological states,
M.S. Clark et al.
being specifically targeted to the problems associated with climate change and their
effects on functional biodiversity.
3.4.4.3 Ecotoxicology Monitoring
Marine ecosystems, particularly coasts, estuaries and coral reefs, are currently
experiencing major crises worldwide as environmental change places significant
physiological stress (metals, pesticides, chemicals but also parasites) on organisms.
Understanding ecosystem resilience and predicting the impact of such environmental stresses on marine organisms depends on knowing the physiological status
and plasticity of these organisms in these ecosystems. Traditional ecotoxicology
in marine species involves the study of “biological biomarkers” such as enzyme
activities and stress protein quantification, immunological parameters evaluation
and life trait (growth, reproductive stage) evaluation. Recent progresses in genomic
and proteomic techniques have lead to the emergence of new approaches in ecotoxicology called “ecotoxicogenomics”. This is defined as the study of gene and protein
expression in non-model organisms that is important in understanding responses to
environmental toxicant exposures. Ecotoxicogenomics is a technology that has been
made possible mainly by the advent of DNA microarray analyses. Microarrays have
aided our understanding of relationships between global gene expression profiles,
physiological states of an organism, and traditional toxic endpoints (Irwin et al.
2004, Lee et al. 2003).
Genomics provides a detailed view of physiological diversity and function, and
thus a mechanistic insight into how organisms respond to environmental stress.
Genomic approaches in ecotoxicology will:
• Improve our understanding of toxicant/stress/infection mechanisms.
• Develop a physiological perspective on the environmental facilitation of toxicant/stress/infection within organisms
• Produce tools to predict the spread of toxicant/stress/infection, leading to better
assessment and prediction of environmental health.
In particular, the application of ecotoxicogenomics will extrapolate from experimental in vitro to in vivo systems and across the species barrier. It will aid in the
understanding of specific molecular events underlying the mode of action of toxicants, and therefore these can be developed as biomarkers to identify exposure to
environmental stressors.
Gene expression profiling can be used to show that the specific genes repressed
or induced upon exposure to a toxic stress vary depending on the cell type and the
type of toxicants to which the cells were exposed (Troester et al. 2004). The major
challenge of ecotoxicogenomic approaches will be to take into account intrinsic
sources of variability in gene expression levels due to different physiological states,