Oysters . . .
	In the Classroom

Lab Activity:
Hunting for Hemocytes . . . .

Materials:

• Compound light microscope with 100x oil immersion objective
  
• Glass slides and cover slips
  
• Fresh live oysters
  
• Oyster knife for shucking
  
• Glass capillary pipette, micropipet, or needle (19 gauge) & syringe

Procedure:

1. Carefully shuck the oyster taking care not to damage any tissues. For help see step 11 of the Oyster Anatomy: Internal Laboratory.
   
   
2. Remove the right valve and drain off any excess fluid from the oyster. The oyster should be laying in the left valve or "on the half shell".
   
   
3. Locate the pericardial cavity which contains the heart. See step 17 of the Oyster Anatomy: Internal Laboratory, on the web for the location of the heart.
   
   
4. Using the pipette or the needle and syringe, remove 1 or 2 ml of the hemolymph from the pericardial cavity.
   
   
5. Place a drop of the hemolymph on a glass slide and let it sit undisturbed for 5-10 minutes. This will give the hemocytes time to settle onto the slide and spread their pseudopodia.
   
   
6. Place a cover slip on the drop of hemolymph and focus on the sample under low power. Step up the magnification and focus on an area with a few hemocytes (happy hunting).
   
   
7. Place a drop of oil on the coverslip before using the 100x objective. Focus on the hemocytes and observe their pseudopodia in action.

Wrap-Up:

Have students compare/contrast the hemocytes with their own white blood cells and how the immune system of the oyster is different from that of a mammal.

References:

The Eastern Oyster. Victor S. Kennedy, Roger I.E. Newell, and Albert F. Eble, Eds. Maryland Sea Grant College, University System of Maryland, College Park, MD. 1996.

Oyster Anatomy Lab, http://www.mdsg.umd.edu/issues/chesapeake/oysters/education/anatlab/index.htm. Interactive lesson on oyster anatomy and how to properly "shuck" an oyster.

http://www.mdsg.umd.edu/Extension/msgsnn/msgsnn02_3/oysters_class.html