14136
To evolve species - specific aptamers , twelve rounds of selection to live S . enteritidis and S . typhimurium were performed , alternating with a negative selection against a mixture of related pathogens .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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