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: Using macaque monkeys with different types of MPTP - induced parkinsonism , the current study evaluated the degree to which rate of symptom progression , symptom severity , and response to and duration of levodopa therapy may be involved in the development of LIDs .
### Output Text:
Using macaque monkeys with different types of <span class="chemical">MPTP</span> - induced parkinsonism , the current study evaluated the degree to which rate of symptom progression , symptom severity , and response to and duration of <span class="chemical">levodopa</span> therapy may be involved in the development of LIDs . 