Article Abstract:
Previous studies have reported that Escherichia coli accumulate guanosine 3',5'-bispyrophosphate (ppGpp) and in consequence, develop penicillin tolerance, as a stringent response under conditions of amino acid deprivation. During the stringent response, synthesis of peptidoglycan and penicillin-induced lysis are inhibited in the amino acid-deprived cells. In a recent study of E. coli, peptidoglycan synthesis and penicillin tolerance were shown to result from the inhibition of phospholipid synthesis and not from the production of ppGpp as earlier suggested. This indicates that peptidoglycan metabolism is dependent on phospholipid synthesis during growth of E. coli.
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Article Abstract:
Peptidoglycan, a cell wall polymer, forms a sacculus around most eubacteria. Chlamydia trachomatis and C. pneumoniae are obligate intracellular eubacteria having a unique development cycle, with one form the infectious elementary body (EB), adapted to extracellular survival. It is believed that even if EBs contain peptidoglycan, it is in insufficient quantities to form a sacculus imparting structural stability. The growth of peptidoglycan-containing bacteria is inhibited by penicillin and other Beta-lactam antibiotics, through inhibition of penicillin-binding proteins (PBPs). Data shows that Chlamydia spp. can synthesize peptidoglycan.
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Article Abstract:
This paper describes in-process monitoring of Escherichia coli fermentation in normal and heavy water solvents using Fourier-trnsform proton-NMR spectrometry. Results show that the technique is rapid and versatile for simultaneous, direct and automatic analyses of compounds in the fermentation media.
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