Question

If steam is not applied during the malachite green step, what is a likely result at the end of the staining procedure?

a) Only sporangium will be green.
b) Both spores and sporangium may be green.
c) Both spores and sporangium may be clear.
d) Both spores and sporangium may be pink.

Answer 1

Without steam, both spores and sporangium are likely to remain clear during the endospore staining procedure because the heat from steam helps malachite green penetrate the resistant endospore coat.

Step-by-step explanation:

If steam is not applied during the malachite green step in the endospore staining process, the most likely outcome is that both spores and sporangium may be clear. This is because the heat from the steam acts as a mordant, helping the malachite green penetrate the highly resistant endospore coat. Without this step, the primary stain will not efficiently penetrate the endospore, and after rinsing and counterstaining with safranin, the vegetative cells may pick up the counterstain, but both spores and sporangium could remain unstained and hence, clear.