SEPTEMBER 6-7 - MINUTES OF MEETING 
33 
strains by conjugation (723). He noted that the purpose of the work is 
to identify the genes controlling nitrogen fixation in the donor by 
testing their ability to correct the genetic defect of the mutant strains 
that receive the recombinant DNA. The donor is a cyanobacterium, a 
prokaryotic species that carries out photosynthesis. The Center for 
Disease Control lists all strains of Klebsiella as Class 2 pathogens. 
Dr. Campbell said that the experiments should provide information of 
basic interest in the area of nitrogen fixation. He did not consider 
the experiments to present any danger; however, he felt there are problems 
with the proposal. (1) Klebsiella are CDC Class 2. (2) Dr. Haselkorn' s 
suggestion that the Klebsiella strains be considered HV1 systems is 
inappropriate; no evidence has been presented to suggest a level of 
containment comparable to that observed in E. coli K-12. Currently, 
experiments involving hosts carrying conjugation-proficient plasmids are 
not permitted in E. coli K-12. Dr. Campbell suggested that Dr. Haselkorn 
be asked to supply ORDA with a more detailed description of heteroduplex 
studies indicating how much of the cloned segment actually hybridizes to 
Klebsiella DNA and where the homologous regions are situated. With 
sufficient data, the proposal might be treated as a kind of self-cloning. 
Dr. Campbell suggested that the RAC reject the request as written and 
send it back to Dr. Haselkorn requesting additional information. 
Dr. Novick questioned whether similar experiments could be done using E. 
coli . Dr. Brill responded that the experiment would be more difficult as 
there would be no selection system and the cloned DNA would probably 
be lost without sane type of selective pressure. Dr. Goldstein requested 
further information on Klebsiella in terms of its containment as compared 
to E. coli . Dr. Brill noted that some Anabaena strains produce a very 
potent mammalian neurotoxin. Dr. Brill asked that Dr. Haselkorn address 
this problem. Dr. Campbell moved to reject the proposal as written. The 
RAC accepted the motion to reject the proposal by a vote of sixteen for, 
none opposed, with two abstentions. 
C. Cloning Klebsiella Histidine Biosynthesis and Nitrogen Fixation 
Genes in Saccharomyces 
Dr. Broadbent presented a proposal from Dr. Frederick Ausubel of Harvard 
University to lower the containment level for purified Klebsiella DNA 
segments which had been cloned in Saccharomyces cerevisiae from the P3 + EK2 
level to P2 + EKl on grounds that the purified cloned segments from the 
Klebsiella genome can no longer can be considered to be pathogenic (724). 
He noted that the DNA segments from Klebsiella have been extensively char- 
acterized and known to contain only the his and nif genes. Dr. Brill then 
added that there is no potential problem m the case of the pCRAlO clone. 
This is also true for Dr. Ausubel' s internal nif clones. The problem 
arises with other clones which contain additional ENA. Dr. Young pointed 
out that pathogenicity involves a whole constellation of characteristics. 
The ENA to be used in this proposal is well-characterized and inserting 
this type of cloned ENA into yeast is probably not going to introduce the 
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