2254
In contrast , overexpression of mouse butyrylcholinesterase ( BChE ) , a proven stoichiometric bioscavenger of OP compounds , protected 5 out of 6 mice from DFP lethality and surviving mice showed no symptoms of DFP toxicity .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities:  
Answer:
 None