culturing a host transformed by {HEAD ~ a vector} comprising {TAIL ~ a DNA segment} having the following nucleotide sequence: 
culturing a host transformed by { HEAD ~ a vector } comprising { TAIL ~ a DNA segment } having the following nucleotide sequence :
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH