Occurrence of non-N-substituted glucosamine residues in lysozyme-resistant peptidoglycan from Bacillus cereus cell walls

Effects of Lysozyme on Bacillus cereus 569: Rupture of Chains of Bacteria and Enhancement of Sensitivity to Autolysins

“…However, when the enzymes were added separately, only a pre-treatment with lysozyme followed by autolysins gave stimulated rates of lysis, indicating that lysozyme must act on sensitive regions of the wall, thus increasing accessibility or susceptibility to autolysins. Lysozyme caused little decrease in the turbidity of suspensions of walls of B. cereus in the studies of Hughes (1971) and Araki et al (1972) and no release of 14C from [14C]GlcNAclabelled walls (D. Westmacott, unpublished results). The small but significant decrease in turbidity demonstrated in this paper may have been due to alteration in the compactness of the walls.…”

“…Assay of free reducing groups in lysozyme-treated isolated walls Strains of B. cereus differ in the proportion of unacetylated glucosamine residues found in their peptidoglycan and hence in their susceptibility to lysozyme (Araki et al, 1972). To characterize the biochemical basis for the enhancement of autolytic activity in strain 569 brought about by lysozyme, we examined the release of free reducing groups.…”

“…Hughes (1971), in his study of the products of cell wall digestion during autolysis of B. cereus NRRL 569, demonstrated the resistance of walls to lysozyme at concentrations as high as 100 pg ml-l. This resistance is due specifically to the deacetylation of N-acetylglucosamine residues of the wall peptidoglycan (Araki et al, 1972;Hayashi et al, 1973) and this is also the factor responsible for lysozyme resistance in B. subtilis and B. megaterium (Hayashi et al, 1973). Araki et al (1971) showed that B. cereus possesses a deacetylase which is specific for undegraded peptidoglycan, thus indicating that N-acetylglucosamine residues in the glycan are deacetylated after completion of polymerization of the peptidoglycan.…”

The diacetamidodideoxyuronic-acid-containing glycan chain of Bacillus stearothermophilus NRS 2004/3a represents the secondary cell-wall polymer of wild-type B. stearothermophilus strains

“…), and then centrifuged for 1 h at 17700g (Araki et al, 1972). The pellet was resuspended in 200 ml pre-warmed 50 mM sodium phosphate buffer, pH 7.5, and then digested with 20 mg trypsin for 2 h at 37 "C. The precipitate colIected from the trypsin digest by centrifugation at 1OOOOg for 1 h was treated with 250 ml 0.4% SDS at room temperature for 1 h, washed six times with distilled water (48400 8, 20 min) and lyophilized, giving approximately 1 g of cell walls.…”

Γονιδιωματική Ανάλυση Και Λειτουργικός Χαρακτηρισμός Ασύνηθων Συστημάτων Αμινοακυλίωσης Του Μεταφορικού RNA Σε Παθογόνους Μικροοργανισμούς

“…Αντιθέτως, πρώτα μετατρέπεται σε Sep-tRNA Sec από μια Ο-φωσφοσερυλ-tRNA κινάση (PSTK) (Carlson et al, 2004) και έπειτα το Sep-tRNA μετατρέπεται σε Sec-tRNA μέσω της δράσης της συνθάσης Sep-tRNA:Sec-tRNA (SepSecS) (Yuan et al, 2006, Xu et al, 2007 παρουσία σεληνιοφωσφορικού (Leinfelder et al, 1988) et al, 1968). Η γλυκάνη παρουσιάζει ελάχιστες διαφοροποιήσεις, όπως ακετυλίωση ή φωσφορυλίωση της υδροξυλομάδας στη θέση 6 του μουραμικού οξέος (Araki et al, 1971, Ghuysen, 1968, Liu & Gotschlich, 1967 και κατά περίσταση απουσία ενός πεπτιδίου ή Ν-ακέτυλο συστατικού (Ghuysen, 1968, Araki et al, 1971b. Σε διαφορετικούς οργανισμούς, ο μέσος όρος του μήκους της αλυσίδας είναι από 10 έως 65 μονάδες δισακχαριτών (Ghuysen, 1968, Hughes, 1970 To πεπτιδικό τμήμα της πεπτιδογλυκάνης εξυπηρετεί τη σύνδεση μεταξύ των μονομερών (Εικόνα 24) (Rogers et al, 1980).…”