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: The ability of insulin treatment to reverse or prevent the changes in urinary bladder function caused by streptozotocin - induced diabetes mellitus .
### Output Text:
The ability of insulin treatment to reverse or prevent the changes in urinary bladder function caused by <span class="chemical">streptozotocin</span> - induced diabetes mellitus . 