3 
plasmid). When a nonconjugative vector is used, the 
E. coli K-12 host may contain conjugation-proficient 
plasmids, either antonomous or integrated or generalized 
transducing phages." 
III. Pi Laboratory Practices 
The Division of Safety, NIH, has prepared signs which we recommend 
that you use in each Pi laboratory. The smaller one could be affixed 
outside the door of a Pi laboratory. The larger one could be put 
on a wall inside a PI laboratory. One set of these signs is being 
distributed to each Institutional Biosafety Committee. Additional 
copies of the signs can be obtained from the Office of Recombinant 
DNA Activities, Room 4A52, Building 31, NIH, Bethesda, MD 20205. 
IV. Use of Ff Bacteriophages 
As mentioned in the decision document accompanying the proposed 
revised Guidelines in the Federal Register of November 30, 1979, 
and until further action by the NIH, investigators may continue 
using Ff bacteriophages at the containment levels specified by the 
1978 Guidelines. For example, the cloning of primate DNA in E. coli 
K-12, currently proceeding at the P3 + EKl containment levels 
under the 1978 Guidelines, may continue using Ff bacteriophages at 
EKl, but must remain at the P3 level of physical containment. 
V. Ongoing Projects and Adoption of New Containment Levels 
Ongoing projects involving E. coli K-12 host-vector systems may be 
carried out under the new containment levels as soon as the require- 
ments of Section III-O of the Guidelines have been fulfilled. This 
involves registration with the local IBC. 
VI. Notification to NIH 
Principal Investigators should inform ORDA and the appropriate NIH 
program administrator of NIH awards if their ongoing work, which 
previously required registration of a Memorandum of Understanding 
and Agreement (MUA) with NIH, now involves only experiments described 
in Section III-O of the revised Guidelines. This information will 
be used to delete your award from the listing of awards supporting 
recombinant DNA research that requires registration with NIH. If 
in addition to work falling under Section III-O, an award supports 
C3] 
