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Publications archive - Biodiversity

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Key departmental publications, e.g. annual reports, budget papers and program guidelines are available in our online archive.

Much of the material listed on these archived web pages has been superseded, or served a particular purpose at a particular time. It may contain references to activities or policies that have no current application. Many archived documents may link to web pages that have moved or no longer exist, or may refer to other documents that are no longer available.

Review of the Project: The Development of a Cane Toad Biological Control (February 2003)

D. Hazell, R. Nott and M. F. Shannon
Department of the Environment and Heritage, August 2003


Term of Reference 2

The likelihood of the project achieving the proposed 1 and 3-year objectives, which have a time frame beyond the current approved funding.

1-year Objectives

  1. Continuation of passaging in cell culture for attenuation
    • On the basis of progress thus far this aim is considered achievable.
    • This aim is ongoing for three years.
  2. Continuation of targeted attenuation by insertion/deletion in up to 4 non-essential genes of a ranavirus.
    • This is achievable.
    • This aim is ongoing for three years.
  3. Construction of prototype viruses containing either adult globin or tadpole globin (control construct).
    • This is achievable.
  4. Development of technology for producing a recombinant that does not contain antibiotic resistance genes.
    • This is achievable.
  5. Testing in tadpoles of genes found in the current micro-array screening.
    • This is achievable.
  6. Creation of a subtracted library to search for further differentially expressed genes.
    • This is achievable.
    • This should be a priority.
  7. Produce a gene subtracted library on micro arrays to look for species-specific genes as well as more potential target genes.
    • This is achievable.
    • This should be a priority.
  8. Investigate the new technologies that would build on the efficacy of the proposed concept.
    • This is achievable.
    • This should be a priority.

Three-year Objectives

  1. Attenuation of virus by passaging in cell culture as well as deletion/interruption of one or more non-essential genes.
    • This is achievable.
  2. Construction of a prototype virus containing adult globin, tadpole globin or other potential targets identified in Canberra.
    • This is achievable.
    • It should be possible by this stage to focus on other potential targets.
    • Construction of prototype virus with either adult of tadpole globin should be completed within 1 year.
  3. Testing of potential recombinant/attenuated viruses in a number of indicator species as well as cane toad tadpoles.
    • A more substantial plan for comprehensive testing needs to be developed.
    • This is not a trivial task (see Term of Reference 3) and should precede the proposed aim as currently stated.
  4. Creation of a recombinant virus lacking antibiotic resistance genes.
    • This is achievable.
    • The researchers have a reasonable plan to achieve this.
  5. Assessment of level of expression of foreign genes using different promoters.
    • This is achievable.
    • Once this task has been undertaken in tissue culture it will need to be tested in toads or tadpoles since promoters can behave very differently in an in vivo situation compared to cell culture conditions.
  6. Development of a ranavirus as a vector for delivery of new biological products (based on new technology).
    • This is achievable.
  7. Continuation of identification of metamorphosis genes using micro array analysis.
    • This is achievable.
  8. Investigation and characterisation of the beta globin switching phenomena.
    • This objective seems peripheral and unnecessary for achieving the overall project aim.
  9. Development of the new approaches (integrated with dot point 6)
    • This is achievable.
  10. Development of the use of micro arrays to identify cane toad specific genes.
    • This is achievable.
  11. Use of subtracted libraries to search for further differentially expressed genes expressed at low levels.
    • This is achievable.
  12. Refinement of micro array analysis of gene expression across development using thyroid hormone.
    • This aim may take longer than 3 years to complete but is achievable given the expertise of the researchers.

Findings from Term of Reference 2

  1. The likelihood of achieving both the one-year and three-year objectives is high.
  2. Refinement of the micro array analysis for all the studies outlined in the three-year objectives is likely to continue past the three-year timeframe
  3. A Comprehensive plan for testing of native species, both for the specificity of the genes isolated as well as for virus attenuation, needs to be established and some of this testing commenced.
  4. Complete testing will take considerably longer than 3 years.