{TAIL ~ Certain reducible compounds} are useful in analytical compositions, elements and methods, e.g. for assays of {HEAD ~ bacterial cells} 
{ TAIL ~ Certain reducible compounds } are useful in analytical compositions , elements and methods , e.g. for assays of { HEAD ~ bacterial cells }
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD