teratoma. [terâ²ÉtÅâ²mÉ] pl. teratomas, teratomata. a tumor composed of different kinds of tissue, none of which normally occurs together or at the site of the tumor. Teratomas are most common in the ovaries or testes.
The pink-colored film or ring frequently seen on showers, tubs, toilets and pet water bowls is typically caused by growth of the airborne bacteria Serratia marcesens. This harmless nuisance organism reacts with standing water and frequently forms during spring and summer months.
Because of the naure of their cell wall, Gram-negative bacteria stain pink after Gram staining. 2. The Gram-negative cell wall consists of 2-3 interconnected layers of peptidoglycan surrounded by an outer membrane. 3. Peptidoglycan prevents osmotic lysis in the hypotonic environment in which most bacteria live.