1-What is meant by diffrential stain? At which step in the gram staining process

Question

1-What is meant by diffrential stain? At which step in the gram staining process arevthe cells first differentiated?

2-which genera produce endospores?

3-name two diseases thatvare caused by endospore producing bacteria.

4-why do gram positive vagetative cells stain red from safranin during the endospore stain and do not appear red during the gram stain?

5-what do only the acid fast stain and endospore stain have in common. Explain whe this step is necessary in both staining procedures

6- why at first glance why does it appear that both bacteria are motile in the hanging drop prepration ?

7- what are the possible flageller arrangements of bacteria?

8- what makes up the thick protictive coat around an endospore?

9-what isnthe propose of the oil used during oil immersion?

10-what compound is responsible for the acid fast properties of acid fast positive bacteria like mycobacterium?

Explanation / Answer

1)

The term differential stain refers grams stinging:

Gram staining is a technique used to differentiate bacteria based on their cell walls. First step of the Gram stain is the application of crystal violet; this stains all microbes in the sample purple. The second step involves the application of Gram’s iodine; it is a mordant factor that causes the crystal violet to form granules that embed within the cell wall of bacteria.

Gram positive bacteria have thicker cell walls, so this crystallization is more extensive and permanent in these bacteria. The third step involves applying alcohol; this removes much of the outer layer of the cell wall and washes the crystals off of Gram-negative cells. Once removed, the Gram-negative cells are now colorless, so a red dye (safranin) is applied as a last step to show their presence.

2)

The endospores produced by Bacillus and Clostridium.

3)

7)

The possible flagella arrangements of bacteria are:

8)

An Endospore is a non-reproductive, dormant and tough bacterial structure, which is produced by bacterial phylum known as Firmicute. Endospores have calcium and dipicolinic acid, and they can survive at high temperatures (100° C) for about 30 minutes.   

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