{HEAD ~ Further objects} are {TAIL ~ processes} for the preparation and purification of said proteins, mRNAs, DNAs and hybrid vectors, and processes for the preparation of hosts containing said hybrid vectors 
are
{ HEAD ~ Further objects } are { TAIL ~ processes } for the preparation and purification of said proteins , mRNAs , DNAs and hybrid vectors , and processes for the preparation of hosts containing said hybrid vectors
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH