27883
The rise of melatonin at dusk induces a separate and distinct cohort , including the clock - regulated genes Cry1 and Nampt , but little is known of the up - stream mechanisms involved .
 Chemical: melatonin
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: melatonin