These Questions Are in regards to Staining techniques. Endospores 1) Under what

Question

These Questions Are in regards to Staining techniques.

Endospores

1) Under what conditions are endospores usually formed?

2) How do Bacillus and Clostridium genera differ in their oxygen preference?

3)After Staining, why do endospores appear green but the rest of the cell pink?

4) Name 3 diseases caused by anaerobic endospore forming organisms and one caused by aerobic endospore forming organisms.

Acid Fast Stain

1) The mycobacteria appear fuchsia with an Acid Fast Stain and purple with a Gram Stain. Explain his phenomenon.

2) Why is it desireable to combine S. aureus with acid fast organisms such as M. smegmatis when applying the Acid Fast staining technique?

3) Name two human diseases and their causative agents where the Acid Fast stain is used in diagnosis.

Would greatly appreciate as detailed of an answer as possible.

Explanation / Answer

1. Endospores usually form under nutrient deprivation and harsh environmental condition where the bacteria feel difficulting survive to protect themselves from these extreme conditions.

2. Bacillus is aerobic bacterial genera, requires oxygen for their survival, but clostridium is anaerobic bacterial genera, oxygen is toxic to them. In case of other characteristics, both genera will show several of similarities.

3. Endospore usually stained by malachite green, so the appearance of green indicates the presence of endospore and the rest of vegetative cell counter-stained by safranin which usually appears in pink.

4. Gas gangrene, Tetanus and Botulism caused by anaerobic clostridium bacteria species and Anthrax by bacillus aerobic bacteria.

1. Its lipid-rich cell wall sometimes makes it resistant for Gram-stain in mycobacterium tuberculosis. So that the Zeihl-Neelsen acid-fast staining (carbolfuchsin) will stain the mycobacterium mycolic acid present in the cell wall and gives bright red fluorescence after acid-alcohol wash under methylene blue counterstain background. Gram-staining will detect the peptidoglycans in the cell wall and retains the crystal violet or purple color after alcohol wash under safranin counterstain pink color. The positive result for these two staining confirms the mycobacterium infection since, it is gram positive mycolic acid-containing bacteria.

2. It is desireable to combine S. aureus with acid-fast organisms such as M. smegmatis when applying the Acid Fast staining technique, because the initial stain carbolfuchsin binds with M. smegmatis and the counter-stain methylene blue will be taken up by S. aureus and appears in blue at a time single experiment same chemicals but identifying two pathogens..

3. Tuberculosis; Mycobacterium spp., Nocardiosis; Nocardia spp. Both are pulmonary infections.

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