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PubMed1978

The nuclear magnetic resonance determination of the conformation of saccharides bound in subsite D of lysozyme.

The binding of the trisaccharide (2-acetamido-2-deoxy-D-muramic acid)-beta(1 leads to 4)-(2-aceta-mido-2-deoxy-D-glucosyl)-beta(1 leads to 4)-(2-acetamido-2-deoxy-D-muramic acid) to subsites B, C, and D in lysozyme has been studied by 1H nuclear magnetic resonance methods. In particular, the coupling constant between H1 and H2 of the reducing saccharide bound in subsite D has been determined. The coupling constant for the bound saccharide indicates that the dihedral angle between C1 and C2 for the reducing saccharide is not significantly changed upon binding to lysozyme. This result is discussed in terms of other evidence for the role of distortion of the saccharide bound in subsite D in the lysozyme-catalyzed hydrolysis of cell wall oligosaccharides.

Binding Sites↗
PubMed1987

Structural requirements of muramylpeptides for induction of necrosis at sites primed with Mycobacterium tuberculosis in guinea pigs.

Intracutaneous injection of N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) in guinea pigs caused an extensive necrotic reaction in footpads prepared by injection of heat-killed Mycobacterium tuberculosis in water-in-mineral-oil emulsion. We examined a variety of analogs and derivatives of muramylpeptides for their ability to provoke this reaction. A maximum and a minimum structure responsible for the necrotic reaction were found to be N-acetylglycosaminyl-beta(1-4)-N-acetylmuramyl-tripeptide (GlcNAc-MurNAc-L-Ala-D-isoGln-meso-A2pm) and MDP, respectively. An unexpected finding was that GlcNAc-MurNAc-tetrapeptides having L-amino acids at their C termini, unlike comparable compounds having C-terminal D-amino acids, exhibited definite necrosis-inducing activity, probably due to their tendency to undergo in vivo degradation to GlcNAc-MurNAc-tripeptide. Introduction of some acyl groups, especially the stearoyl group, to the 6-O position of the muramic acid or the peptide moiety of muramylpeptides increased the necrosis-inducing activity of the parent molecules. However, this was not observed with 1-thio-muramic acid analogs of MDP. Modification of the alpha- or gamma-carboxyl groups of the glutamic acid residues of muramylpeptides tended to decrease their necrosis-inducing ability. Analogs and derivatives of muramylpeptides which are capable of inducing necrosis at a primed site, with few exceptions, exhibited powerful adjuvanticity against ovalbumin in guinea pigs. However, the reverse was not necessarily true.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1999

Structural analysis of Bacillus megaterium KM spore peptidoglycan and its dynamics during germination.

The composition and structure of peptidoglycan from dormant spores of Bacillus megaterium KM and its dynamics during germination were investigated. Amino acid analysis and mass spectrometry identified 21 muropeptides resolved by reverse phase HPLC following digestion of peptidoglycan with Cellosyl. The basic structure of peptidoglycan in B. megaterium spores is similar to that of Bacillus subtilis: 44.2% of muramic acid residues are substituted with delta-lactam, 28.8% with single L-alanine, 25.1% with tetrapeptide and only 1.8% with tripeptide. The cross-linking index of the spore peptidoglycan, determined from muropeptides resolved by reverse phase HPLC, was 2.2 % per muramic acid. Spore peptidoglycan contains 2.9% of muropeptides with unsubstituted N-acetylmuramic acid. These muropeptides are likely to be intermediate products of delta-lactam formation. Analysis of muropeptide dynamics during germination revealed the activity of at least two hydrolytic enzymes, an N-acetylglucosaminidase and a lytic transglycosylase. A 4 M LiCl extract from 30 min germinated spores of B. megaterium KM caused 'germination-like' changes to permeabilized spores of B. megaterium and B. subtilis but not those of a B. subtilis cwlD mutant. Muropeptide analysis of the treated spores revealed the presence of products generated by the activity of a glucosaminidase.

Acetylglucosaminidase↗
PubMed1989

Incorporation of bacterial peptidoglycan constituents into macrophage lipids during phagocytosis.

It has previously been established that several glycopeptides of peptidoglycan origin are formed as a result of processing of Bacillus subtilis cell walls by the macrophage-like cell line RAW264. Although the formation of these glycopeptides could account for the humoral immune responses characteristic of bacterial peptidoglycans, their formation does not account for the cellular-mediated immune responses observed for water-in-oil emulsions of peptidoglycan or for lipophilic derivatives of glycopeptide fragments thereof. Therefore, the processing of peptidoglycan by macrophages was reexamined to establish whether the lipophilic derivative of any peptidoglycan-derived glycopeptide was formed. The experiments were performed by incubating B. subtilis cell walls radiolabeled in muramic acid, glucosamine, alanine, glutamic acid, and diaminopimelic acid residues in the presence of the macrophage-like cell line RAW264. The crude lipid fraction derived from the macrophages was further fractionated and analyzed, revealing the presence of two lipophilic glycopeptides that contained glucosamine, muramic acid, and alanine of bacterial origin.

Alanine↗
PubMed2006

[Effects of specific microbial biocides on N transformation in soil with glucose amendment].

In an incubation test of soil with glucose amendment, two kinds of nitrogenous fertilizer and three kinds of specific microbial biocides were applied, and the contents of soil NH(4+)-N, NO3(-)-N, glucosamine and muramic acid were measured to differentiate the relative contribution and timing characteristics of soil microbes in nitrogen immobilization. The results showed that penicillin and streptomycin decreased the transformation rate of NH(4+)-N markedly, with more significant effects than actidione. The amount ratio of glucosamine to muramic acid after applying penicillin and streptomycin rapidly increased first, and tended to equilibrium then. With the application of actidione, the transformation rate of NO3(-)-N decreased continuously, and the synthesis of glucosamine was inhibited, while penicillin and streptomycin had no significant effects on them. At the early stage of incubation, bacteria could rapidly immobilize both NH(4+)-N and NO3(-)-N, with NH(4+)-N preferred, while at the later stage of incubation, fungi were the dominant contributor to nitrogen transformation, and had much stronger ability of utilizing NO3(-)-N than bacteria.

Anti-Bacterial Agents↗
PubMed1976

Immunochemical analysis of an unusual cell wall polysaccharide from animal coagulase-positive staphylococci. 1. Fragments obtained after hydrolysis in hydrofluoric acid and alkali.

Polysaccharide P (poly P) of canine coagulase-positive staphylococci contains glycerol, glucose, glucosamine, muramic acid, phosphate, and the usual peptidoglycan amino acids, but does not cross-react serologically with standard teichoic acids. Products from hydrolyses in hydrofluoric acid and alkali contained phosphates of glycerol and glucose as well as combinations of these, but neither glucosyl-glycerol units nor glucosamine-phosphates were observed. The teichoic acid of poly P is probably a polymer of a repeating unit consisting of alternating glycerol, phosphate and glucose.

Alkalies↗
PubMed1994

A urinary marker for occult systemic coccal disease.

Gram-negative particles, found in 'normal' urine by an improved microscopic technique, become excessive (often > 10(5)/ml) in many systemic diseases. In these diseases they are accompanied by sparse, usually fastidious, gram-positive cocci. Antibiotics at moderate doses usually have little effect. Larger doses of antibiotics suppress, or temporarily eliminate, the particles. In this report, the particles are characterized by light microscopy for better identification. Then, by detection of muramic acid in a hydrolysate and by transmission electron microscopy, they are identified as decomposed ('exploded') gram-positive cocci. Since explodeds cannot be external contaminants, and their precursors cannot proliferate sufficiently in urine, they must have crossed renal membranes to come from within the body. They are demonstrated in tissue fluids and in synovial fluids by optical microscopy, by their muramic acid, and by transmission electron microscopy. Thus, they cross other membranes. Explodeds are excessive in several rheumatic diseases, in renal diseases, in diseases in which a coccal cause has been sought, and in some in which cocci have never been considered. There is no precedent for explodeds. Their appearance and numbers are compatible with the literature on natural and experimental systemic streptococcal diseases and with the experimental illnesses following injection of streptococcal cell walls. Urinary explodeds are likely to be the end result of the 'almost physiological' entry of streptococci into the circulation which necessitates predental antibiotic prophylaxis in mitral disease. Increased numbers of urinary explodeds probably represent excessive entry of precursors or proliferation of precursors within the host. Urinary explodeds serve as a marker for diverse systemic diseases, systemic coccal disease.

Adult↗
PubMed2000

Length distribution of the peptidoglycan chains in the sacculus of Escherichia coli.

The stress-bearing fabric of bacteria is made of peptidoglycan. This crosslinked fabric is formed from disaccharide pentapeptide units that are transported through the cytoplasmic membrane and then polymerized in two directions: (i) to form oligoglycan chains; and (ii) to cross link these chains by tail-to-tail bonds from the muropeptides to the protruding peptides of other chains. The distribution of the glycan chain lengths is reminiscent of the "most probable distribution of polymer chemistry. Of course, the process is more complex than solely the random addition of units to growing chains. The complexity precludes mathematical analysis, but computer modeling of the Monte Carlo type is capable of including a range of possibilities. At each time point a specified number of disaccharides are singly added to the muramic acid residue ends of existing chains chosen at random. The transfer is in exchange for the cleavage of pyrophosphate bactoprenol that transported the disaccharide pentapeptide through the membrane. The progam then selects, again at random, which chain to cleave and between which two disaccharides of the chain the cleavage event is to occur. The cleavage generates an N -acetyl 1,6 anhydro-muramic acid end and a non-reducing N -acetyl glucosamine end. The simulation can be modified so that the program does not cleave off a disaccharide next to either end of the chain. Comparisons are shown with the experimental results of Obermann & H]oltje (1994. Microbiology140, 79-87.) They obtained their data by taking the results with normal growing cells and subtracting the similar data from minicells to estimate the chain length distribution in the cylinder part of the cell. In its most basic form the computer simulation has only one fitted parameter, K, which is the number of disaccharides added to the murein for every internal cleavage event. In this form the fitting to the experimental results is poor. One possible reason for this is that the tension on the chains, and therefore the probability of being cleaved by autolysins varies with orientation of the chain on the cylinder surface. It is well known that the tension in the cylindrical wall is twice as large in the circumferential direction as in the axial one, so one class would consist of those chains aligned longitudinally, subject to lower stress, and would have a higher energy of activation for autolysis than chains aligned circumferentially. A good fit is obtained on the assumption that there are only two classes of chains; one more likely to be cleaved than the other. The key point is that only two processes: adding of disaccharide pentapeptides at random to glycan chains and cleavage between the disaccharides at random, together with the assumption that the wall is less easily hydrolysed in the axial direction is sufficient to account for the experimental distribution.

Cell Wall Skeleton↗
PubMed1983

Chemical characterization of extracellular polysaccharides produced by Actinomyces viscosus T14V and T14Av.

The human isolates Actinomyces viscosus T14V and T14Av produced extracellular polysaccharides in the absence of sucrose. In contrast to strain T14V, strain T14Av produced abundant viscous slime polysaccharide in the culture supernatant fluids when grown in a chemically defined medium containing glucose. After resolution of the T14Av polysaccharides into seven fractions, it was demonstrated that two of these exhibited viscous properties and lacked methylpentose and muramic acid. The major slime polysaccharide purified by gel filtration and ion-exchange column chromatography contained 39% (moles percent carbohydrate) galactose, 37% N-acetylglucosamine, 19% glucose, and 5% mannose. Only trace amounts of protein and phosphorus were detected in this preparation. On the other hand, strain T14V produced negligible slime polysaccharide under the same culture conditions. The major extracellular polysaccharide fraction from this strain contained methylpentoses, hexoses, hexosamines, muramic acid, protein, and phosphorus, suggesting that this fraction might be derived from the cell wall.

Actinomyces↗
PubMed1999

Salmonella-triggered reactive arthritis: use of polymerase chain reaction, immunocytochemical staining, and gas chromatography-mass spectrometry in the detection of bacterial components from synovial fluid.

OBJECTIVE: To investigate whether microbial components are present in the cells of synovial fluid or peripheral blood from patients with Salmonella-triggered reactive arthritis (ReA). METHODS: Synovial fluid cells and/or peripheral blood cells from 23 patients with Salmonella-triggered ReA and from 19 control patients with newly diagnosed rheumatoid arthritis were studied using 3 different polymerase chain reaction (PCR) techniques and immunocytochemical staining. Muramic acid from the synovial fluid was studied by gas chromatography-mass spectrometry. RESULTS: Salmonella chromosomal DNA was not detectable in the synovial fluid cells and peripheral blood leukocytes of patients with Salmonella ReA. Initially, positive reactions were observed in the synovial fluid cells and peripheral blood leukocytes of 3 of 17 and 3 of 18 patients with ReA, respectively, but in the subsequent PCR studies, these findings were not reproducible. Salmonella-specific antigen was detectable by immunofluorescence in the synovial fluid cells and peripheral blood leukocytes of 4 of 11 and 2 of 7 patients with ReA, respectively. Muramic acid was present in 2 of 15 synovial fluid samples from patients with ReA, but the bacterial cultures from synovial fluid were negative. CONCLUSION: These findings indicate the presence of bacterial degradation products, but not bacterial DNA, in the inflamed joints of patients with Salmonella-triggered ReA.

Adolescent↗
PubMed1989

Somnogenic activity of O-acetylated and dimeric muramyl peptides.

Slow-wave sleep-promoting factors in brain and urine were identified as muramyl peptides (MPs), the building blocks of bacterial cell wall peptidoglycan. In this study, structural variations of MPs that occur naturally in bacterial peptidoglycan were investigated for somnogenic activity. Monomeric and dimeric MPs were isolated and purified from Neisseria gonorrhoeae and Actinomadura sp. strain R39. The structures of these MPs were verified by fast atom bombardment mass spectroscopy and tandem mass spectroscopy. After intracerebroventricular administration of MPs, electroencephalograms and brain temperatures of rabbits were recorded for 6 h and were analyzed to determine durations of slow-wave sleep, rapid-eye-movement sleep, and wakefulness. The 6-O acetylation of muramic acid enhanced the somnogenic effects of certain monomeric MPs relative to their non-O-acetylated (but otherwise identical) counterparts. Two monomeric MPs containing an unsubstituted amide (i.e., Iso-Gln) were inactive, thus confirming previous results showing that amidation of a variety of MPs can block somnogenic activity. Two peptide-cross-linked MP dimers tested had no effect on slow-wave sleep, although a third peptide-cross-linked MP containing a 1,6-anhydro muramyl end on one of its monomeric subunits, a structure that enhances somnogenic potency of un-cross-linked monomers, was somnogenic. Two dimers connected by glycosidic bonds and containing an Iso-Gln moiety were inactive. Two other glycosidically linked dimers that also contained an Iso-Gln moiety, but were of lower molecular weight, were somnogenic. In summary, 6-O acetylation of muramic acid in somnogenic MPs enhances activity, and as a class, peptide-linked dimeric MPs tend to be less active than their constituent monomers.

Acetylation↗
PubMed1999

Gordonia polyisoprenivorans sp. nov., a rubber-degrading actinomycete isolated from an automobile tyre.

A rubber-degrading bacterium (strain Kd2T) was isolated from fouling tyre water inside a deteriorated automobile tyre. The strain was aerobic, Grampositive, produced elementary branching hyphae which fragmented into rod/coccus-like elements and showed chemotaxonomic markers which were consistent with the classification of Gordonia, i.e. meso-diaminopimelic acid, N-glycolyl muramic acid, arabinose and galactose as diagnostic sugars, a fatty acid pattern composed of unbranched saturated and monounsaturated fatty acids with a considerable amount of tuberculostearic acid, and mycolic acids comprising 58-66 carbon atoms with two principal mycolic acids C60 and C62 counting for over 60%. Results of 16S rDNA analyses as well as chemotaxonomic results, led to the conclusion that Gordonia sp. strain Kd2T (= DSM 44302T) represents a new species within the genus Gordonia for which the name Gordonia polyisoprenivorans is proposed.

Actinomycetales↗
PubMed1976

Chemical composition and turnover of peptidoglycan in Neisseria gonorrhoeae.

The peptidoglycan of all four colonial types of a number of strains of Neisseria gonorrhoeae constituted 1 to 2% of the dry weight of the cell. The chemical composition of cell types examined was similar with molar ratios of 1:1:2:1:1 for muramic acid, glucosamine, alanine, glutamic acid, and diaminopimelic acid, respectively. Ninety-six percent of the mass of the peptidoglycan was composed of these compounds. A lipoprotein analogous to that observed in Escherichia coli was not detected. The chain length of the glycan varied from 80 to 110 disaccharide units. The peptide contained equimolar amounts of D- and L-alanine. The rate of turnover of peptidoglycan in strain RD5 was 50% per generation. Turnover proceeded without a lag and followed first-order kinetics.

Alanine↗
PubMed1968

Peptidoglycan of a chemolithotrophic bacterium, Ferrobacillus ferrooxidans.

The rigid layer (peptidoglycan) of the wall of the chemolithotroph Ferrobacillus ferrooxidans was isolated after various chemical treatments. The removal of specific components was followed by noting in an electron microscope changes in the appearance of the cell surface. The final peptidoglycan was virtually free from proteins and was sensitive to the action of lysozyme. Results of chemical analyses of acidhydrolyzed peptidoglycan revealed three major amino acids and two amino sugars: glutamic acid, alpha,epsilon-diaminopimelic acid, alanine, glucosamine, and muramic acid in a ratio of 1:1:2.33:062:088.

Alanine↗
PubMed1977

Ultrastructure of Nocardia-like variants of Mycobacterium smegmatis and chemical composition of the basal cell wall layer.

Mycobacterium smegmatis, its orange-red--pigmented (OR) variants, and back mutant strains were examined by electron microscopy using ultrathin sectioning, negative or positive staining, and freeze-fracture-etching methods. The parental and back mutant strains showed almost identical ultrastructures. Specifically, thick ramified fibers measuring about 15 nm in diameter were always visible in the positively stained cell wall, although they were not readily visualized with negative staining or freeze-fracture-etching. In contrast, the cell walls of OR variants contained fibrous networks measuring about 11 nm in diameter, which could be observed by positive and negative staining as well as freeze-fracture-etching. Although cytoplasmic structures appeared similar among the four strains examined, mesosomes were significantly more abundant in the OR variants. The basal layer of the cell wall obtained as a phenol residue consisted of a dense membranous matrix containing scattered fibrous structures in the parental and back mutant strains, and fibrous networks in the OR variants. Chemical analyses showed that the basal layers of all four strains contained the same neutral sugars, amino sugars, and amino acids, i.e., arabinose, galactose, muramic acid, glucosamine, alanine, glutamic acid, and diaminopimelic acid. The alpha-branched, beta-hydroxylated fatty acids contained in the basal layers differ among the four strains, however, with nocardomycolic acids being present in the OR variants and mycolic acids in the parental and back mutant strains. Our previous conclusion that OR variants of M. smegmatis have characteristics similar to those of nocardia is supported by the present study.

Amino Acids↗
PubMed1976

Studies of the cell envelope of Vibrio para-haemolyticus A55: isolation and purification of bag-shaped peptidoglycan (murein sacculus).

The peptidoglycan (PG) component of the envelope of Vibrio parahaemolyticus A55 was studied in relation to the salt dependency of the organism. A bag-shaped PG (murein sacculus) was isolated and purified by digestion of freshly harvested intact whole cells with sodium dodecyl sulfate (SDS) and then protease treatment. Whole cells lyze in salt-deficient or hypotonic conditions and this can be measured by turbidometry. Lysis is prevented by addition of 0.35 M NaCl or acidification to below pH 4.5. The isolated PG or murein sacculi did not seem to require salt for structural integrity. The PG obtained by the same method from subcellular fractions, that is, envelope fractions, prepared either with or without NaCl, was extensively fragmented. The main amino acids and amino sugars of the murein sacculus were glucosamine, muramic acid, alanine, glutamic acid, 2, 6-diamnopimelic acid (A2pm) in a molar ratio of 0.4:0.6:1.7:0.9:1.0. A polyglucose, which was only degraded by Pseudomonas isoamylase,and poly-beta-hydroxybutyrate (PHBA) were found in the murein sacculus. The murein sacculus of the organism is discussed in comparison with PG of other gram negative bacteria and marine or halophilic microorganisms.

Alanine↗
PubMed2004

Heterogeneity in microbial exposure in schools in Sweden, Poland and Jordan revealed by analysis of chemical markers.

We used gas chromatography--tandem mass spectrometry to analyze microbial components in 85 samples of airborne dust from schools in Jordan, Sweden, and Poland. To collect the samples, we allowed dust to settle on plexiglass plates hanging in the breathing zone in school buildings during both summer and winter. In each of the three countries, we conducted such sampling in two schools: one in an urban environment and the other in rural surroundings. The microbial marker profiles differed significantly between the schools and seasons. For example, samples from Jordan contained remarkably low levels of ergosterol (marker of fungal biomass) and high levels of 3-hydroxy acids (markers of lipopolysaccharide) of 10, 12, and 14 carbon chain lengths relative to such acids of 16 and 18 carbons in comparison with samples from Sweden and Poland. This dissimilarity in 3-hydroxy fatty acid distribution indicates significant differences in the populations of Gram-negative bacteria. We also noted that muramic acid (marker of bacterial biomass) exhibited the smallest variation between schools and seasons. In summary, our results demonstrate that exposure to microorganisms in indoor air in school buildings may differ markedly between countries, between seasons, and between urban and rural environments.

Adolescent↗
PubMed1973

Peptidoglycan of free-living anaerobic spirochetes.

Electron microscope examination of negatively stained or thin-sectioned cells of Spirochaeta stenostrepta treated with penicillin or lysozyme showed that the peptidoglycan was present as a thin, electron-dense layer adjacent and external to the cytoplasmic membrane. The peptidoglycan was isolated from cells of S. stenostrepta and Spirochaeta litoralis by a procedure including treatments with sodium lauryl sulfate and Pronase. Hydrolysates of the isolated S. stenostrepta and S. litoralis peptidoglycans contained glucosamine, muramic acid, glutamic acid, l-ornithine, and alanine in molar ratios of 0.90:0.85:1.00:1.00:1.40 and of 0.63:0.63:0.99:1.00:1.41, respectively. Determination of N-terminal residues suggested that nearly 50% of the ornithine in S. stenostrepta and S. litoralis peptidoglycans was involved in peptide cross-linkage. The peptidoglycan layer of S. stenostrepta was sensitive to lysozyme and myxobacter AL-1 protease.

Alanine↗