6782
Interaction of the Fur repressor with a 150 - bp fragment encompassing the pvdS promoter was demonstrated in vivo by the Fur titration assay and confirmed in vitro by gel retardation experiments with a partially purified Fur preparation .
 GENE: Fur repressor; GENE: pvdS promoter; GENE: Fur; GENE: Fur
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: GENE 
Text: {0} 
 Entities: Fur repressor, pvdS promoter, Fur, Fur 
Answer:
 GENE: Fur repressor; GENE: pvdS promoter; GENE: Fur; GENE: Fur