Dr. DeWitt Stetten, Jr. 
February 27, 1976 
Page 5 
discuss the issue, I did not comment at that time; however, during 
the meeting on February 9-10, in listening to Dr. Hogness and 
Dr. Brown, I though that a rationale for EK1 containment for insects 
should be put into the guidelines. If cold-blooded vertebrates are 
indeed felt to pose a hazard, the insects do not pose any less of a 
hazard in "shotgun" experiments. Thus, perhaps EK2 should be used 
for all insects as well, especially if Dr. Curtiss’s progress in the 
development of an approved EK2 makes the safer organism available 
very shortly. In that case, there seems to be very little rationale 
for using an EK1 as a host vector for the insect class. Also, the 
use of embryonic or germ-line DNA was thought to be safer than other 
DNA from cold-blooded vertebrates. Dr. Margery Shaw in her concluding 
statement did not feel that embryonic material was necessarily 
"cleaner", although horizontal infection might be less likely. The 
examples quoted above of spirochetal and viral infection of 
Drosophila eggs represent on instance in which embryonic material is 
infected. There are undoubtedly many others. 
4. My last point concerns genetically active DNA released by 
bacterial cells dying in an animal host. DNA has been demonstrated 
to be genetically active in the mouse. In fact, Griffith's 1928 
experiments involved the transformation of living pneumococci b^ 
DNA released from dead pneumococci in mice. Austrian, in 1952, 
demonstrated transformation of pneumococci with DNA injected at a 
distant site in several species of mammals . Several other invest- 
igators have done similar experiments; thus, even though it might 
be expected that extracellular DNA would be extensively digested 
in animals, some DNA can resist degradation and retain genetic 
activity in vivo. 
If there are risks in this type of research, the genetic activity 
of released DNA must be considered, not only the survival of the 
host microorganism. 
* Austrian, R. Observations of the possible role of neucleic acid 
exchange reactions in pneumococcdLcapsulaC type transformation. 
Bulletin of the Johns Hopkins Hospital, 90:170, 1952. 
Conant, J. E. and W. D. Sawyer. Transformation during mixed pneumococcal 
infection of mice. J. Bact. 93:1869, 1967. 
Nightingale, E. 0. Competence of pneumococcal isolates in bacterial 
transformations in man. Infection and Immunity. 6:785, 1972. 
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