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To grow and divide efficiently a bacterial cell wall must add new
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Peptidoglycan to its cell wall in a precise and well regulated way while maintaining wall shape and integrity in presence of high osmotic pressure
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Because cell wall peptidoglycan is essentially a single enormous network
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The growing bacterium must be able to degrade it just enough to provide acceptor ends for the incorporation of new peptidoglycan units
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It must also recognise
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Peptidoglycan when necessary
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Limited peptidoglycan digestion is accomplished by enzyme known as
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Autolysins
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Some of which attack
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Polysaccharide chains
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While other hydrolyse
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Peptide cross links
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Autolysin inhibitors keep the activity of these
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Enzymes under tight control
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Although location and distribution of
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Cell wall synthetic activity varies with species
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Many gram positive cocci eg enterococcus faecalis and streptococcus pyogenes
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Have only one to a few zones of growth
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The principle growth zone is usually at the site of
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Septum formation
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And new cell halves are
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Synthesized back to back
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The second pattern of synthesis occurs in
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Rod shaped bacteria escherchia coli salmonella and bacillus
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Active peptidoglycan synthesis occur at the site of
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Septum formation just as before
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But growth sites are also scattered along
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Cylindrical portion of the rod
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Thus growth is distributed more diffusely in
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Rod shaped bacteria than streptococci
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