Lecture 5: Bacterial Oxygen Requirements Flashcards
Why is oxygen essential for obligate anaerobes?
Because it serves as the final electron acceptor in the electron transfer chain, and without it the final step (protein IV) cannot be used.
Why is oxygen toxic for some organisms?
Because it has forms that are highly reactive; they can form radicals that cause great damage to the interior of cells that are not equipped to handle it.
What are the four toxic forms of oxygen?
Singlet oxygen. (1O2)
Superoxide radical (O2-)
Peroxide anion (O2 2-)
Hydroxyl radical (OH-)
What is singlet oxygen? (1O2)
What is a superoxide radical? (O2-)
What is a peroxide ion? (O2 2-)
What is a hydroxyl radical?
What are facultative anaerobes?
What are aerotolerant anaerobes?
Name an example of “good bacteria”.
What are microaerophiles?
Organisms that are damaged by the 21% concentration of atmospheric oxygen, and require lower amounts of oxygen, such as the 2-10% in the stomach.
What are some examples of microaerophiles?
Helicobacter pylori.
What bacterial infections do injecting drug users commonly get?
In non-severe cases, bacterial infections can involve staphylococcus aureus and other skin-colonising bacteria.
In severe cases, clostridium spores can be present on the needle and this can be deadly.
Why are clostridia a common cause of these infections?
Because they can forms spores, and
What characteristics do severe IDUs have?
- They spread rapidly from point of infection.
- They cause severe tissue and muscle damage
- Cause hypotension, and shock.
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