23479
Studying transgenic mice with superoxide dismutase 1 gene mutations , widely used as model for ALS , may provide a better understanding of pathogenic mechanisms and of toxicity towards motor neurons , also possibly helping to understand whether treatments for ALS should take into account sexual dimorphism .
 Chemical: superoxide
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: superoxide