In {HEAD ~ such a reagent}, the liberated nucleic acids are protected from {TAIL ~ nuclease degradation} by the ionic detergent 
In { HEAD ~ such a reagent } , the liberated nucleic acids are protected from { TAIL ~ nuclease degradation } by the ionic detergent
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH