UNIVERSITY OF SOUTH CAROLINA 
COLUMBIA, S. C. 29208 
DEPARTMENT OF BIOLOGY 
August 21, 1978 
Dr. Donald S. Fredrickson 
Director 
National Institute of Health 
Bethesda, Md. 20014 
Dear Dr. Fredrickson: 
I am writing you concerning the proposed revision of the NIH 
Guidelines for Recombinant DNA Research. First let me say that I 
am very much in favor of the revision. I think that the original 
estimation of the potential biological hazards was overstated and 
unrealistic. Clearly many dangerous pathogens can be studied more 
safely after they have been dismantled using "recombinant DNA tech- 
niques". Also, the exemption from the Guidelines of bacteria which 
exchange genetic material with IS. coli will eliminate a lot of red 
tape without any additional risk. 
With regard to this last point, I would like to request that 
Caulobacter crescentus be included in the list of exchangers that 
is exempt from the Guidelines. I have previously shown that 15. coli 
and C^. crescentus exchange plasmids (Abs. Ann. Meeting Amer. Soc. 
for Microbiol. 1978:109). Additional data is in the enclosed manu- 
script which I have submitted for publication in GENETICS. In this 
manuscript, I present data demonstrating exchange of chromosomal genes 
between IS. coli andl Caulobacter crescentus (p.9). This exchange 
proceeds in either direction and is dependent upon the presence of a 
drug resistance factor in the donor. I feel that these data are 
quite sufficient to meet the criteria for exchanges as described in 
section I-E-4 of the Guidelines and that Caulobacter crescentus 
should be included in the list of exchangers in Appendix A of the 
proposed Revision. Thank you in advance for your help on this matter. 
Sincerely 
Bert nry 
Assistant Professor 
BE :kf 
[A-34] 
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