Question
Action of lysozymes on gram negative bacteria ‑
| A. |
Faster than gram positive bacteria
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| B. |
Has no action
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| C. |
Depends on integrity of outer membrane
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| D. |
Cause resistance to antibiotic
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Show Answer
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Correct Answer � C
Explanation
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|
Ans. is ‘c’ i.e., Depends on integrity of outer membrane Ref Fundamentals of food microbiology 6th/e p. 496
- Lysozyme is an acetyl – mura midase which cleaves bond between N-acetylmuramic acid and N-acetyl – D-glucosamine residues in peptidoglycan of all wall.
- Gram-positive bacteria are sensitive to action of lysozymes -› lysozymes cause lysis of gram-positive bacteria easily.
- Gram-negative bacteria are less susceptible and are protected by outer membrane, which is the outer most covering in gram negative bacteria (outside the cell wall) and has barrier function.
- However, lysozyme can cleave the peptidoglycan layer of Gram-negative bacteria if this layer is exposed by membrane attack complex (MAC or C5-9) of complement which destroys outer membrane.
- (Note : gram positive bacteria do not have outer membrane thus lysozymes directly act on cell membrane).
