In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: At termination of the experiments , mice underwent echocardiography , quantitation of abundance of molecular markers of CM ( ventricular mRNA encoding atrial natriuretic factor [ ANF ] and sarcoplasmic calcium ATPase [ SERCA2 ] ) , and determination of plasma LA .
### Output Text:
At termination of the experiments , mice underwent echocardiography , quantitation of abundance of molecular markers of CM ( ventricular mRNA encoding atrial natriuretic factor [ ANF ] and sarcoplasmic <span class="chemical">calcium</span> ATPase [ SERCA2 ] ) , and determination of plasma <span class="chemical">LA</span> . 