In the image, what do dark blue locations represent?

In the image, what do dark blue locations represent?

• A. Epithelial cell nuclei
• B. Total bacteria
• C. Fusobacterium
• D. Bacteroides

Answer: (A)

Dark blue regions indicate DNA-rich nuclei because the stain used highlights nuclear material. In epithelial tissue, each cell contains a nucleus that appears as a dark blue oval or circle. Bacteria are much smaller and would not form the large, discrete blue spots that mark cell nuclei; they would either be faint, a different color, or require a specific probe to be visible. So those dark blue locations are epithelial cell nuclei.

Dark blue regions indicate DNA-rich nuclei because the stain used highlights nuclear material. In epithelial tissue, each cell contains a nucleus that appears as a dark blue oval or circle. Bacteria are much smaller and would not form the large, discrete blue spots that mark cell nuclei; they would either be faint, a different color, or require a specific probe to be visible. So those dark blue locations are epithelial cell nuclei.