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PubMed2006

The entry mechanism of membrane-containing phage Bam35 infecting Bacillus thuringiensis.

The temperate double-stranded DNA bacteriophage Bam35 infects gram-positive Bacillus thuringiensis cells. Bam35 has an icosahedral protein coat surrounding the viral membrane that encloses the linear 15-kbp DNA genome. The protein coat of Bam35 uses the same assembly principle as that of PRD1, a lytic bacteriophage infecting gram-negative hosts. In this study, we dissected the process of Bam35 entry into discrete steps: receptor binding, peptidoglycan penetration, and interaction with the plasma membrane (PM). Bam35 very rapidly adsorbs to the cell surface, and N-acetyl-muramic acid is essential for Bam35 binding. Zymogram analysis demonstrated that peptidoglycan-hydrolyzing activity is associated with the Bam35 virion. We showed that the penetration of Bam35 through the PM is a divalent-cation-dependent process, whereas adsorption and peptidoglycan digestion are not.

Bacillus Phages↗
PubMed1987

Elimination of group A streptococcal cell walls from mammalian tissues.

The precise levels in mammalian tissues of rhamnose (a constituent of the group-specific polysaccharide) and muramic acid (a constituent of peptidoglycan) at various times after systemic administration of streptococcal cell walls were noted for the first time. The extreme resistance of the streptococcal cell wall to degradation by mammalian enzymes can now be clearly appreciated. The results help explain the chronic nature of certain inflammatory diseases elicited by streptococcal cell wall debris.

Animals↗
PubMed2000

Synthesis and biological evaluation of analogues of bacterial lipid I.

Bacterial Lipid I analogues containing different anomeric groups at the muramic acid moiety were synthesized and screened in MurG enzyme assays run in the presence and absence of cell wall membranes. The results obtained in this study help elucidate the role of the lipid diphosphate in the recognition of Lipid I by MurG.

Bacteria↗
PubMed1979

Fine structure of the Legionnaires' disease bacterium. In-vitro and in-vivo studies of four isolates.

We obtained four bacterial isolates from patients with Legionnaires' disease and examined them for in-vitro and in-vivo fine-structure characteristics. All isolates had an outer membrane, cytoplasmic membrane, and intracellular membrane structure. Numerous intracellular inclusions were seen, particularly from in-vivo specimens, and appeared membrane-limited. Fine-structure analysis did not reveal the presence of a definitive peptidoglycan structure. Isolation, purification, and chemical analysis of Legionnaires' disease bacterium pepdoglycan established molar ratios of alanine-glutamic acid and muramic acid-glucosamine. Diaminopimelic acid was absent in the Legionnaires' disease bacterium peptidoglycan. The Kellenberger procedure for fixation appears to be the best method for the fine-structure determination of Legionnaires' disease bacteria.

Alanine↗
PubMed2005

Requirements of peptidoglycan structure that allow detection by the Drosophila Toll pathway.

The Drosophila immune system is able to discriminate between classes of bacteria. Detection of Gram-positive bacteria involves a complex of two pattern recognition receptors: peptidoglycan recognition protein SA (PGRP-SA) and Gram-negative binding protein 1 (GNBP1). These activate the Toll signalling pathway. To define the cell wall components sensed by the host, we used highly purified peptidoglycan fragments of two principal Gram-positive bacterial pathogens Staphylococcus aureus and Streptococcus pneumoniae. We report that in both peptidoglycans, the minimal structure needed to activate the Toll pathway is a muropeptide dimer and that the free reducing end of the N-acetyl muramic acid residues of the muropeptides is essential for activity. Monomeric muropeptides were inactive and inhibitory in combination with dimers. Finally, peptidoglycan was degraded by the haemolymph of wild-type but not GNBP1 mutant flies. We suggest a model whereby GNBP1 is involved in the hydrolysis of Gram-positive peptidoglycan producing new glycan reducing ends, which are subsequently detected by PGRP-SA.

Animals↗
PubMed1996

Lytic transglycosylases.

Although cleaving the same glycosidic bond between MurNAc and GlcNAc in murein, lytic transglycosylases differ from lysozymes by catalyzing an intramolecular transglycosylation of the glycosyl-bond onto the C6 hydroxyl group of the muramic acid residue yielding 1.6-anhydromuramic acid-carrying products. The three dimensional structure of the soluble lytic transglycosylase Slt70 of E. coli revealed a doughnut-like shape that would allow the protein to encircle the polysaccharide strands of the murein. Despite the absence of significant sequence homology, the catalytic center shows structural similarity to lysozymes, although the catalytic aspartate is missing. All lytic transglycosylases which have been characterized up until now turned out to be processive exo-glycosylases.

Bacterial Proteins↗
PubMed2000

Bacterial cell wall-induced arthritis: chemical composition and tissue distribution of four Lactobacillus strains.

To study what determines the arthritogenicity of bacterial cell walls, cell wall-induced arthritis in the rat was applied, using four strains of Lactobacillus. Three of the strains used proved to induce chronic arthritis in the rat; all were Lactobacillus casei. The cell wall of Lactobacillus fermentum did not induce chronic arthritis. All arthritogenic bacterial cell walls had the same peptidoglycan structure, whereas that of L. fermentum was different. Likewise, all arthritogenic cell walls were resistant to lysozyme degradation, whereas the L. fermentum cell wall was lysozyme sensitive. Muramic acid was observed in the liver, spleen, and lymph nodes in considerably larger amounts after injection of an arthritogenic L. casei cell wall than following injection of a nonarthritogenic L. fermentum cell wall. The L. casei cell wall also persisted in the tissues longer than the L. fermentum cell wall. The present results, taken together with those published previously, underline the possibility that the chemical structure of peptidoglycan is important in determining the arthritogenicity of the bacterial cell wall.

Animals↗
PubMed1996

Lysozyme substrates.

The natural substrate of lysozyme is the rigid layer of bacterial cell walls, the murein (peptidoglycan), which is a gigantic polymer of (GlcNAc-MurNAc)n polysaccharide strands crosslinked through short peptide bridges at the lactyl groups of the muramic acid residues. Thus, lysozyme lyses bacteria by degrading their protective exoskeleton, the murein sacculus. The high molecular weight murein is thereby hydrolysed to low molecular weight muropeptides, a process that can be followed quantitatively by different methods. However, due to the insolubility of the murein sacculus, the enzyme kinetics are rather complex. Therefore, a variety of different low molecular weight substrates have been prepared, both murein degradation products and synthetic compounds. These substrates allow a better characterization of the binding and catalytic mechanism of lysozyme. In addition, they are used in various photometric, isotopic and immunological lysozyme assays.

Carbohydrate Sequence↗
PubMed2006

Actinocatenispora thailandica gen. nov., sp. nov., a new member of the family Micromonosporaceae.

Two actinomycete strains, TT2-10(T) and TT2-3, which produced long spore chains (more than 10 spores per chain), were isolated from peat swamp forest soil in Pattaloong Province, Thailand. Their taxonomic positions were determined using a polyphasic approach. The chemotaxonomic characteristics of these strains coincided with those of the family Micromonosporaceae, i.e. cell-wall chemotype II, muramic acid of the N-glycolyl type, whole-cell sugar pattern D and type II phospholipids. Analysis of the 16S rRNA gene sequences also indicated that these strains constitute a distinct lineage within the family Micromonosporaceae, sharing 91.3-93.8 % sequence similarity with members of this family. On the basis of their phenotypic and genotypic characteristics and their phylogenetic position, these strains represent a novel genus and species, for which the name Actinocatenispora thailandica gen. nov., sp. nov. is proposed. The type strain of Actinocatenispora thailandica is strain TT2-10(T) (=JCM 12343(T)=PCU 235(T)=DSM 44816(T)).

Carbohydrates↗
PubMed1988

Selective pivaloylation of 2-acetamido-2-deoxy sugars.

Selective pivaloylation of 2-acetamido-2-deoxy-D-glucose, its methyl alpha- and beta-glycosides, and the methyl alpha-glycoside of N-acetyl-D-muramic acid under various conditions has been studied. The structures of the products were established by 1H-n.m.r. spectroscopy and acetylation. The orders of acylation, HO-6 greater than HO-3 greater than HO-1 greater than HO-4 for 2-acetamido-2-deoxy-D-glucose and HO-6 greater than HO-3 greater than HO-4 for its methyl glycosides, were established. Methyl 2-acetamido-2-deoxy-3,6-di-O-pivaloyl-alpha- and -beta-D-glucopyranosides and 2-acetamido-2-deoxy-1,3,4,6-tetra-O-pivaloyl-D-glucopyranose were hydrolysed by rabbit serum esterases.

Acetylglucosamine↗
PubMedDate not supplied

[Determination of cell wall amino sugars in Streptococcus on a carbohydrate analyzer].

A method of determining aminosaccharides (muramic acid, glucosamine and galactosamine) by means of a carbohydrate analyzer "Biotronic" using the cation-exchange resin DC-6 A ("Durrum") was developed. Chromatographic conditions correspond to the conditions of neutral sugar analysis on a column with DCh-4 resin, that enables after a slight modification of the analyzer to pass from the determining of aminosaccharides to the determining of neutral sugars. The method was used for determining the carbohydrate composition of streptococcus cell walls. The results obtained allow to conclude that using this method one can get more information on the hydrocarbon composition of various biological objects than using the method of aminosaccharide determining by means of aminoacid anylyzer, which is widely in practice nowadays.

Amino Sugars↗
PubMed2003

Role of peptidoglycan subtypes in the pathogenesis of bacterial cell wall arthritis.

BACKGROUND: Bacterial cell wall (CW) arthritis develops in susceptible strains of rats after a single intraperitoneal injection of the CW from certain bacterial species, both pathogenic and non-pathogenic. For the development of chronic bacterial CW arthritis, the structure of the bacterial peptidoglycan (PG) has been found to be decisive. OBJECTIVE: To define the role of PG subtypes in the pathogenesis of chronic bacterial CW arthritis. METHOD: Arthritis was induced with CWs of Lactobacillus plantarum, L casei B, L casei C, and L fermentum. Gas chromatography-mass spectrometry was used to measure the presence of CW derived muramic acid in the liver and to determine PG subtypes. CWs were also tested for their resistance to lysozyme in vitro. RESULTS: These results and those published previously indicate that PGs of CWs which induce chronic arthritis, no matter whether they were derived from strains of Streptococcus, Bifidobacterium, Collinsella, or Lactobacillus, all have lysine as the third amino acid of the PG stem peptide, representing PG subtypes A3alpha and A4alpha. Those strains which induce only transient acute arthritis or no arthritis at all do not have lysine in this position, resulting in different PG subtypes. CONCLUSIONS: In vivo degradation of only those PGs with the subtypes A3alpha and A4alpha leads to the occurrence of large CW fragments, which persist in tissue and have good proinflammatory ability. CWs with other PG subtypes, even if they are lysozyme resistant, do not cause chronic arthritis, because the released fragments are not phlogistic. It is emphasised that a variety of microbial components not causing inflammation have been found in animal and human synovial tissue.

Animals↗
PubMed1981

Effect of penicillin G on release of peptidoglycan fragments by Neisseria gonorrhoeae: characterization of extracellular products.

The effect of penicillin G (penG) on the turnover and release of peptidoglycan (PG) by Neisseria gonorrhoeae RD5 was investigated. We previously showed that exponentially growing gonococci (labeled in the glycan moiety with glucosamine and muramic acid and in the peptide with diaminopimelic acid) turn over ca. 35% of their PG per generation. In current studies, addition of penG accelerated the rate of PG hydrolysis by more than twofold and resulted in a corresponding increase in the amount of soluble PG fragments found in the medium. This increase of soluble PG was accounted for mainly by the release of nonreducing (anhydro-muramyl-containing) disaccharide peptide dimers (molecular weight, about 2,000) and trimers that were composed of subunits, linked not by peptide cross-linking bonds, but probably only by glycosidic bonds. The enhanced release of these products suggested that penG, directly or indirectly, stimulates the activity of a glycan-splitting, gonococcal PG:PG-6 muramyl transferase (transglycosylase). PG monomers that were released in the presence of penG were identical, both qualitatively and quantitatively, to the monomers released as a result of turnover in the absence of penG and consisted of anhydro-muramyl-containing disaccharide tripeptides and tetrapeptides. PenG-treated bacteria consistently released slightly less free disaccharide and free peptides than did control cultures, implying a penG-associated depression in the activity of the gonococcal N-acetylmuramyl-L-alanine amidase. In addition to stimulating the release of PG fragments, penG was also associated with greatly enhanced release from cells of glucosamine-containing non-PG macromolecule(s).

Hydrolysis↗
PubMed2000

Assay for lytic transglycosylases: a family of peptidoglycan lyases.

An assay has been developed to monitor the activity of the lytic transglycosylases which does not involve the use of radiolabel. Samples of lytic transglycosylase were incubated with isolated and purified insoluble peptidoglycan as substrate for varying lengths of time. Residual insoluble material was removed by ultracentrifugation in a microfuge and the solubilized components were treated with sodium borohydride prior to acid hydrolysis. The optimal conditions for this acid hydrolysis were established to be incubation at 96 degrees C for 1 h in 6 M HCl, in vacuo. The hydrolyzed samples were subjected to amino acid/sugar analysis by cation-exchange chromatography on a Beckman System Gold amino acid analyzer. To effect a clear resolution of muramic acid from serine and glutamic acid, the equilibration buffer was modified to be composed of 33 mM sodium citrate, pH 3.12. The product of the lyase reaction of the lytic transglycosylases are 1,6-anhydromuramyl residues, which are not reduced by the sodium borohydride treatment. On the other hand, the muramyl residues arising at the reducing ends of peptidoglycan after treatment with muramidases (hydrolyases) are reduced to muramitol residues, which elute from the amino acid analyzer prior to aspartic acid. This assay thus distinguishes the activity of the two enzymes and was applied to determine the initial activities of increasing concentrations of a soluble derivative of lytic transglycosylase B from the opportunistic pathogen Pseudomonas aeruginosa.

Amino Acids↗
PubMed1981

Primary structure of the wall peptidoglycan of leprosy-derived corynebacteria.

The cell walls isolated from axenically grown leprosy-derived corynebacteria were submitted to various chemical and enzymatic degradations. The glycan strands of the wall peptidoglycan are essentially composed of N-acetylglycosaminyl-N-acetylmuramic acid disaccharide units. Small amounts of N-acetylglycosaminyl-N-glycolylmuramic acid (less than 10%) were also detected. The muramic acid residues of adjacent glycan strands are substituted by amidated tetrapeptide units which, in turn, are cross-linked through direct linkages extending between the C-terminal D-alanine residue of one tetrapeptide and the mesodiaminopimelic acid residue of another tetrapeptide. Such a structure is very similar to that of the wall peptidoglycan found in the taxonomically related microorganisms of the Corynebacterium, Mycobacterium, and Nocardia groups.

Corynebacterium↗
PubMed1965

The isolation of structural components present in the cell wall of Bacillus licheniformis N.C.T.C. 6346.

1. Four of the known components of wall preparations of vegative cells of Bacillus licheniformis N.C.T.C. 6346 have been isolated free of each other after successive treatments of the walls with trichloroacetic acid and lysozyme: (a) a mucopeptide consisting of glucosamine, muramic acid, alphain-diaminopimelic acid, glutamic acid and alanine in the molar proportions 1.0:0.8:1.0:1.2:1.7; (b) an insoluble protein; (c) teichoic acid containing phosphorus and glucose in equimolar amounts; (d) teichuronic acid containing equimolar amounts of N-acetylgalactosamine and glucuronic acid, as found by Janczura, Perkins & Rogers (1961). 2. Evidence has been obtained for the presence in the soluble fraction obtained by lysozyme treatment of whole walls of a stable covalent complex of the teichoic acid and the mucopeptide components. 3. The molar ratio of phosphorus to glucose in the teichoic acid present in intact walls or the soluble fractions obtained by extraction of the walls with lysozyme or trichloroacetic acid is 1.0:0.25, in contrast with values of about unity obtained for the purified teichoic acid. 4. Intact walls have been shown to contain polyribitol phosphate chains bearing different amounts of glucose substituents. 5. Trichloroacetic acid extracts of walls also contain polyribitol phosphate compounds of different chain lengths. Dialysis of trichloroacetic acid extracts removes the short chains of polyribitol phosphate that have been found to carry only very low amounts of glucose side chains. By contrast, the longer chains present in the non-diffusible fraction contain phosphorus and glucose in almost equimolar amounts.

Bacillus↗
PubMed2001

Proposal of Mycetocola gen. nov. in the family Microbacteriaceae and three new species, Mycetocola saprophilus sp. nov., Mycetocola tolaasinivorans sp. nov. and Mycetocola lacteus sp. nov., isolated from cultivated mushroom, Pleurotus ostreatus.

The taxonomic positions of 10 tolaasin-detoxifying bacteria, which were isolated from the cultivated mushroom Pleurotus ostreatus, were investigated. These strains are Gram-positive, obligately aerobic, non-sporulating and irregular rod-shaped bacteria. They have the following characteristics: the major menaquinone is MK-10, the DNA G+C content ranges from 64 to 65 mol%, the diamino acid in the cell wall is lysine and the muramic acid in the peptidoglycan is an acetyl type. The major fatty acids are anteiso-C15:0 and anteiso-C17:0. On the basis of morphological, physiological and chemotaxonomic characteristics, together with DNA-DNA reassociation values and 16S rRNA gene sequence comparison data, the new genus Mycetocola gen. nov. is proposed for these bacteria in the family Microbacteriaceae and three new species are also proposed: Mycetocola saprophilus sp. nov. (type strain CM-01T = IFO 16274T = MAFF 211324T = NRRL B-24119T), Mycetocola tolaasinivorans sp. nov. (type strain CM-05T = IFO 16277T = MAFF 211325T = NRRL B-24120T) and Mycetocola lacteus sp. nov. (type strain CM-10T = IFO 16278T = MAFF 211326T = NRRL B-24121T). The type species of the genus is Mycetocola saprophilus sp. nov.

Actinomycetales↗
PubMed2006

Phycicoccus jejuensis gen. nov., sp. nov., an actinomycete isolated from seaweed.

A marine actinomycete strain, designated KSW2-15(T), was isolated from a dried seaweed sample collected from a sandy beach on the coast of Jeju in the Republic of Korea. The organism produced non-motile, non-endospore-forming, Gram-positive, coccoid cells. The colonies were circular, translucent and yellow in colour with entire margins. meso-Diaminopimelic acid was present as the diamino acid of the peptidoglycan. The acyl type of the muramic acid was acetyl. Mycolic acids were not present. The predominant menaquinone was MK-8(H(4)). The polar lipids were phosphatidylethanolamine, phosphatidylinositol and diphosphatidylglycerol. The major cellular fatty acids were of the saturated, unsaturated and iso-branched methyl types. The DNA G+C content was 74 mol%. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain KSW2-15(T) formed a loose association with 'Candidatus Nostocoida limicola', within the radiation of the family Intrasporangiaceae of the suborder Micrococcineae. The organism showed the highest levels of sequence similarity with 'Candidatus Nostocoida limicola' (96.1 %), Terrabacter tumescens (96.1 %) and Terrabacter terrae (96.0 %). The levels of 16S rRNA gene sequence similarity between the isolate and members of other genera of the family Intrasporangiaceae were in the range 92.1-95.5 %. On the basis of the polyphasic evidence, the isolate should be classified within a novel genus and species, for which the name Phycicoccus jejuensis gen. nov., sp. nov. is proposed. The type strain of Phycicoccus jejuensis is strain KSW2-15(T) (=KCCM 42315(T)=NRRL B-24460(T)).

Actinomycetales↗