2006 - Progress

 

Areas for cooperation

• Construction of standard databases (Atlas database) on Silurana (Xenopus) tropicalis tadpoles exposed to EE2.
• Metamorphosis assay: Screening of a few thyroid hormone responsive genes.

 

2006 - Objectives

 

Support of OECD Test guideline development using S.tropicalis

• Metamorphosis assay:
  • Phase II validation work close to completion - using X. laevis.
  • Potential for use of X. tropicalis as alternative model
• Partial Life cycle:
  
  • Many benefits of X. tropicalis eg. life cycle - duration of test.
  • Use for higher tier tests for:
    • - thyroid activity (impact of alteration of larval development)
    • - oestrogenic/androgenic activity (comparison to fish)

• Areas for cooperation

• Development and validation of partial life-cycle exposure methods:
  • Assess impacts in adult of larval exposure to thyroid active chemicals and estrogenic/ androgenic chemicals - Construction of standard databases (Atlas database) on Silurana (Xenopus) tropicalis tadpoles exposed to EE2.
  • ‘Ring testing’ methods between UK-Japan
• Metamorphosis assay:
  • Development of other biomarkers relevant in larval life stage eg. for estrogenic action (estrogens can inhibit metamorphosis) - Screening of a few thyroid hormone responsive genes.
• Partial Life cycle:
  • Application of estrogenic/anti-androgenic activity - build on Japanese work
  • Development of further markers indicating Mode of Action
  • Use of histological analysis
• Linkage of histological and genetic/protein markers to apical endpoints eg. reproduction

 

Collaborative Achievements up to 2005

• Data exchange for breeding and larval growth for Silurana tropicalis
• Partial cloning of ERa, ERß, TRa and aromatase genes for S. tropicalis
• Expression analysis for ER genes in the gonad and kidney of S. tropicalis

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2005 - Progress against Objectives

 

Development of environmental impact assessment tools and databases for assessing amphibian populations

• Collection of field survey methods and databases for UK and Japan. Use of GIS system to overlap amphibian population status and changes with land use and land changes. Specific regions in UK have been selected for detailed study.
• Environmental water sampling and testing of samples collected in UK show oestrogencic activity in frog hepatocyte bioassay.
• More extensive analysis of sites has been undertaken using YES and YAS

Development of environmental assay tools

• Cloning of ERs, THRs and aromatase and analysis of their developmental expression
  
• Construction of cDNA library for X. tropicalis, and isolation of a few oestrogen responsive genes.
• Preliminary work on isolation of VTG from wild frog species for VTG ELISA development

The Model Test

• Testing the model developed in the field and in the laboratory (ring test)- not yet initiated 

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2005 - Objectives

 

Development of environmental assay tools

• Field investigations of ecological impacts of EDCs (information gathering)
• Establishing field exposure test methods
• Environmental sampling and testing for EDCs in relevant freshwater bodies
• Establishing ecological information database

Development of biological test methods

• Developing ecological impact test tools:
  • for genes and proteins (e.g. VTG assays)
  • reporter assays for ER and THR (for standard and native species)

The Model Test

• Testing the model developed in the field and in the laboratory (ring test) 

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