Attachment IV - Page 2 
Anne Vidaver 
Comments regarding Dr. Alexander's suggestions (Pg. 107, Feb. 6, 1984, NIH meeting 
transcri pt) . 
1. I don't understand (and apparently it wasn't made clear then or later what was 
meant by 'transport'). But the PWG Guidelines, no. 7,8,9,10 and 11 ask for 
various types of 'survival information' as I understand the term. 
2. Sensitivity of the counting method. This is partly covered by PWG Guidelines 
no. 6, 9, 10 and 11. In my estimation, it is the sampling methods and extent of 
sampling which potentially could limit detection, not the qualitative recovery 
i.e. sensitivity. Qualitative recovery appears feasible with all proposals so 
far submitted to the PWG. Admittedly, this could and should be tested at some 
time i.e. this might be a point for a risk assessment workshop to consider. 
3. The PWG did not address the question of 'escapes' from greenhouse or growth 
chambers beyond what is already in the general guidelines, which I think are 
sufficient. I don't think it's necessary, but a general statement by the PWG 
may be in order to remind anyone planning on constructing recombinant organisms 
for agricultural purposes that they should take appropriate steps to monitor and 
contain their organisms or plants at all testing stages. Such steps are likely 
to vary with the systems studied, so that detailed guidelines at this time would 
seem unncessary. I think the IBCs should deal with this in general terms for 
their conditions and on a case-by-case basis. 
4. Known hos.ts : this is covered by the PWG guidelines, 6, 9 and 10. But I don't 
know what he means here: it is a practical impossibility to test all plants for 
ability to support growth ( as opposed to survival ) of microorganisms released 
into the environment. Monitoring of populations of microorganisms and spread of 
recombinant DNA from introduced plants to weeds and/or other economic plants in 
the vicinity is part of PWG Guideline 6. A modification of no. 12 can be added 
to e: etc... In addition, indicate, if appropriate, how border plants and weed 
species will be monitored for any potential transfer of recombinant DNA. (This 
concern would be part of a risk assessment workshop). 
5. General information about soils in which plants will be grown should be given. 
However, the complexity and types of microflora and microfauna, along with other 
factors, e.g. water and temperature are likely to have a greater impact on 
potential success or failure of introduced microorganisms or plants. I suggest 
a modification to pt. 6 and 12 e: 
6. Ecological factors that would be likely to materially affect the success or 
failure) of introduced micoorganisms should be indicated (e.g. soil type, water, 
wind, temperature). 
12. e. Ecological factors that would be likely to materially affect the success 
(or failure) of the introduced plant should be indicated (e.g. soil type, water, 
temperature) . 
Even with the added information requested, however, it is my guess that it still 
would not satisfy Alexander because, as in a Catch-22 situation, we don't have the 
knowledge base to answer some of these questions to the degree that he apparently 
feels is necessary to proceed. 
With respect to relative risks, we need to remind the public that we indeed do have 
a past history of several thousand years of 'disturbing' the environment. This 
practice, namely farming, incorporates the introduction of new microorgani sms and 
new plants every year. Customary and accepted farming practices, such as crop 
rotation and tillage, change our environment every growing season, and not always 
predictably! 
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