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

Westmacott, D.; Perkins, H. R.

doi:10.1099/00221287-115-1-1

Cited by 38 publications

(23 citation statements)

References 8 publications

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“…From these results it is concluded that the pneumococcus is relatively resistant to lysozyme but that autolysis is affected and stimulated directly because of the limited breakage of the glycan strand by lysozyme. This observation is quite similar to that for Bacillus cereus 569, which is also known to be resistant to lysozyme digestion (19).…”

supporting

confidence: 74%

Enhancement of Autolysis of Streptococcus pneumoniae by Lysozyme

Ohno¹,

Yadomae²,

Miyazaki³

1982

Microbiology and Immunology

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supporting

confidence: 74%

Enhancement of Autolysis of Streptococcus pneumoniae by Lysozyme

Ohno¹,

Yadomae²,

Miyazaki³

1982

Microbiology and Immunology

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“…The presence of non-acetylated aminosugars in the peptidoglycan is not limited to pneumococci (25,26,28,29,33,34), and the increased activity of lysozyme after N-acetylation of partly deacetylated peptidoglycan was also reported in B. cereus (35,36). The data search suggests that, similar to pneumococci in bacilli and other bacterial species, the presence of non-acetylated amino sugars in the peptidoglycan is related to the activity of PgdA-like enzymes.…”

Section: Identification Of N-deacetylated Amino Sugars In the Pneu-mentioning

confidence: 69%

The pgdA Gene Encodes for a PeptidoglycanN-Acetylglucosamine Deacetylase in Streptococcus pneumoniae

Vollmer

Tomasz

2000

Journal of Biological Chemistry

232

125

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Analytical work on the fractionation of the glycan strands of Streptococcus pneumoniae cell wall has led to the observation that an unusually high proportion of hexosamine units (over 80% of the glucosamine and 10% of the muramic acid residues) was not N-acetylated, explaining the resistance of the peptidoglycan to the hydrolytic action of lysozyme, a muramidase that cleaves in the glycan backbone. A gene, pgdA, was identified as encoding for the peptidoglycan N-acetylglucosamine deacetylase A with amino acid sequence similarity to fungal chitin deacetylases and rhizobial NodB chitooligosaccharide deacetylases. Pneumococci in which pgdA was inactivated by insertion duplication mutagenesis produced fully N-acetylated glycan and became hypersensitive to exogenous lysozyme in the stationary phase of growth. The pgdA gene may contribute to pneumococcal virulence by providing protection against host lysozyme, which is known to accumulate in high concentrations at infection sites.The unusual complexity and diversity of the cell surface of Streptococcus pneumoniae is apparent both in the capsular structure and in the underlying cell wall structure of this bacterium, and this complexity and diversity may be related to the multiplicity of interactions of this microbe and its human host. S. pneumoniae is capable of producing at least 90 chemically distinct capsular polysaccharides (1). The cell wall of this microorganism contains a teichoic acid of unusually complex chemistry (2, 3) the components of which include ribitol phosphate, galactosamine, trideoxydiaminohexose, and covalently linked phosphocholine residues (4). The peptidoglycan of S. pneumoniae is also unusual because its stem peptides are cross-linked in both a direct and an indirect manner (5). Furthermore, the proportion of distinct linear and branched muropeptides in the peptidoglycan is clonally related (6). The pneumococcal cell wall is a potential target for components of the first line host defense such as lysozyme. In addition, the peptidoglycan and teichoic acid may represent bacterial ligands recognized by the innate immune system of the host.The recent introduction of high resolution analytical techniques and genetic approaches began to shed light on the determinants and biological functions of the pneumococcal cell wall. In this study we describe the identification of a genetic determinant, pgdA, of the first bacterial peptidoglycan GlcNAc deacetylase. We show that the innate activity of this enzyme is responsible for the high proportion of non-acetylated hexosamine residues in the peptidoglycan that appears to play a role in the resistance of S. pneumoniae to the activity of exogenous lysozyme, an enzyme that is known to accumulate in high concentrations at infection sites. EXPERIMENTAL PROCEDURESBacterial Strains, Plasmids, and Growth Media-Cultures of S. pneumoniae R36A, a non-encapsulated laboratory strain from the Rockefeller University collection, were grown in a casein-based semi-synthetic medium (C ϩ Y) containing 1 mg/ml yeast extract (7) o...

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“…In order to retard this process, we first deactivated the autolytic wall system of staphylococci by chloramphenicol treatment (10,25) and slowly reactivated it afterwards by the addition of a cationic protein (lysozyme at pH 5) which is known to act in staphylococci mainly as an activator of autolytic wall enzymes rather than as a wall-lytic enzyme (28,31). By this procedure, the row of pores in the peripheral cell wall could be better demonstrated (Fig.…”

Section: Resultsmentioning

confidence: 99%

Fan-shaped ejections of regularly arranged murosomes involved in penicillin-induced death of staphylococci

1992

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Electron microscopic research into the murosomes of staphylococci has shown that the number of murosomes involved in penicillin-induced death varies depending on the experimental conditions employed. With 0.1 ,ug of penicillin G per ml, only 1 of a total of about 20 murosomes, the "killing murosome," completely perforated the pressure-stabilized peripheral cell wall during a three-step process. This strictly localized event was mainly attributed to a mechanical effect being comparable to the process of aneurysm formation. Wall perforation was also considered to mark the very moment of penicillin-induced death ("nonlytic killing event"), while bacteriolysis started only postmortem. By varying the osmolarity of the growth medium, the number of murosomes involved in penicillin-induced killing increased considerably, which resulted in the ejection of a fan-shaped row of murosomes at the second division plane. These data are compatible with the finding that, in untreated or chloramphenicol-treated staphylococci, the activation of the murosomes resulted in (i) the formation of regularly arranged "blebs" on the cell surface, containing traces of disintegrated wall material, and (ii) the subsequent liberation of the murosomes lying underneath, leaving behind their former sites in the peripheral wall as a row of regularly arranged "pores" in every division plane. The number, distribution, and positioning of these blebs corresponded with those of the pores and the original murosomes. The significance of wall autolysins liberated from the first division plane for penicillin-induced wall perforation at the second division plane is discussed.

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

Cited by 38 publications

References 8 publications

Enhancement of Autolysis of Streptococcus pneumoniae by Lysozyme

Enhancement of Autolysis of Streptococcus pneumoniae by Lysozyme

The pgdA Gene Encodes for a PeptidoglycanN-Acetylglucosamine Deacetylase in Streptococcus pneumoniae

Fan-shaped ejections of regularly arranged murosomes involved in penicillin-induced death of staphylococci

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