In this task, you are given a sentence. You are expected to write the name of the organism substances in the body mentioned in the input. Although there might be several correct answers, you need to write one of them.
Q:  In a 1 . 5 ml microcentrifuge tube , plasmid ( 1 microg / microl ) and siRNA were mixed with growth medium without fetal calf serum ( FCS ) , 0 . 5 microl 1 . 5 M sucrose and 3 microl X - tremeGENE per microgram nucleic acid to a final volume of 22 . 5 microl .
A: 
serum