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PubMed1999

House dust induces IL-6 and IL-8 response in A549 epithelial cells.

The in vitro potency of house dust to induce cytokine response in A549 lung epithelial cells was studied. Dusts collected from carpet, bed, shelf and floor of a villa and an apartment by vacuuming were found to trigger the production of interleukin-8 (IL-8) and interleukin-6 (IL-6) in a dose-dependent manner, and the interleukin production was several-fold higher than of swine dust (used as a positive control). The IL-8 and IL-6 production of pure Escherichia coli lipopolysaccharide was significantly lower than of the dusts and a peptidoglycan-polysaccharide complex did not show any stimulatory effect at all. The lipopolysaccharide and peptidoglycan contents of the samples were determined by gas chromatography-tandem mass spectrometry analysis of, respectively, 3-hydroxy fatty acids and muramic acid; in addition, ergosterol was monitored for fungal biomass. The inflammatory properties of house dust upon inhalation may be reflected in its high potency to induce cytokine response in lung epithelial cells.

Air Pollution, Indoor↗
PubMed1991

Carbohydrate signatures of aquatic macrophytes and their dissolved degradation products as determined by a sensitive high-performance ion chromatography method.

The sugar contents of emergent macrophytes from a freshwater lake, a freshwater swamp, and a salt marsh in the southeastern United States were examined together with the dissolved free sugars produced during macrophyte degradation and in natural water samples collected adjacent to macrophyte stands. Simultaneous separation of up to 13 neutral and 2 amino sugars together with 3 uronic acids and muramic acid was achieved by anion-exchange high-performance ion chromatography. As little as 10 pmol or a concentration of 20 nM sugar can be detected by pulsed amperometry, a greater sensitivity for sugar quantification than that of previously reported detection techniques used in conjunction with either gas or liquid chromatographic systems. Optimum conditions for hydrolysis of plant material by using trifluoroacetic acid were determined, and internal standards were used to quantify losses due to matrix effects and solid-phase extraction of samples. Our data demonstrate that ratios of certain indicator sugars in undegraded macrophytes differ significantly from ratios of dissolved free sugars formed during macrophyte degradation, reflecting the complex processes (biological and physical) involved in vascular plant degradation in aquatic ecosystems. Natural water samples collected adjacent to macrophyte beds contained dissolved free sugars at concentrations of 620 nM (lake), 890 nM (freshwater swamp), and 2,300 nM (salt marsh). Sugar signatures of these natural water samples were similar to those of macrophyte degradation products.

Journal Article↗
PubMed1983

Purification and quantitative chemical analysis of cell wall peptidoglycans of Leptotrichia buccalis.

Peptidoglycans of Leptotrichia buccalis ATCC 14201 and ATCC 19616 were isolated by extraction with sodium dodecyl sulfate and subsequent digestion of the sodium dodecyl sulfate-insoluble residue with proteases and alpha-amylase. Cell wall fractions obtained by sodium dodecyl sulfate extraction and protease digestion were highly contaminated by a glucose polymer. The polyglucose was removed by alpha-amylase treatment, and the peptidoglycans were left behind. Analyses with amino acids and amino sugars of the cell wall fractions and peptidoglycan specimens revealed that D-glutamic acid, D-alanine, L-alanine, meso-2,6-diaminopimelic acid (A2pm), muramic acid, and glucosamine were the principal components. The dinitrophenylation method revealed that about half of the A2pm residue had a free amino group, and analysis by hydrazinolysis showed that a small part of alanine and A2pm was located at the C terminal. The above results indicate that one of the amino groups of the A2pm residue at one strand of the stem peptide subunit cross-linked to the carboxyl group of alanine of the neighboring strand. It was thus revealed that the peptidoglycans of L. buccalis belong to the A1 gamma type of the classification by Schleifer and Kandler (Bacteriol. Rev. 36:407-477).

Amino Acids↗
PubMed1972

Influence of nutrition on the morphology of a strain of Bifidobacterium bifidum.

A mucoid variant of Bifidobacterium bifidum was converted from its normal curved rod or bifid form to a highly branched form when grown in a chemically defined minimal medium. Branching could be prevented by the addition of a mixture of dl-alanine, dl-aspartic acid, l(+)-glutamic acid, and dl-serine, but not when any one of these four amino acids was omitted. Although sodium chloride induced pleomorphism, calcium ions were ineffective in suppressing the appearance of these pleomorphic forms. None of the cell wall precursors tested, viz., N-acetyl-d-glucosamine, alpha-epsilon-diaminopimelic acid, and muramic acid, inhibited branching.

Acetates↗
PubMed2005

Mycobacterial lipid II is composed of a complex mixture of modified muramyl and peptide moieties linked to decaprenyl phosphate.

Structural analysis of compounds identified as lipid I and II from Mycobacterium smegmatis demonstrated that the lipid moiety is decaprenyl phosphate; thus, M. smegmatis is the first bacterium reported to utilize a prenyl phosphate other than undecaprenyl phosphate as the lipid carrier involved in peptidoglycan synthesis. In addition, mass spectrometry showed that the muropeptides from lipid I are predominantly N-acetylmuramyl-L-alanine-D-glutamate-meso-diaminopimelic acid-D-alanyl-D-alanine, whereas those isolated from lipid II form an unexpectedly complex mixture in which the muramyl residue and the pentapeptide are modified singly and in combination. The muramyl residue is present as N-acetylmuramic acid, N-glycolylmuramic acid, and muramic acid. The carboxylic functions of the peptide side-chains of lipid II showed three types of modification, with the dominant one being amidation. The preferred site for amidation is the free carboxyl group of the meso-diaminopimelic acid residue. Diamidated species were also observed. The carboxylic function of the terminal D-alanine of some molecules is methylated, as are all three carboxylic acid functions of other molecules. This study represents the first structural analysis of mycobacterial lipid I and II and the first report of extensive modifications of these molecules. The observation that lipid I was unmodified strongly suggests that the lipid II intermediates of M. smegmatis are substrates for a variety of enzymes that introduce modifications to the sugar and amino acid residues prior to the synthesis of peptidoglycan.

Cell Wall↗
PubMed1965

Autolytic mechanism for spheroplast formation in Bacillus cereus and Escherichia coli.

Mohan, Raam R. (Warner-Lambert Research Institute, Morris Plains, N.J.), Donald P. Kronish, Roland S. Pianotti, Ray L. Epstein, and Benjamin S. Schwartz. Autolytic mechanism for spheroplast formation in Bacillus cereus and Escherichia coli. J. Bacteriol. 90:1355-1364. 1965.-Spheroplasts of Bacillus cereus strain T and Escherichia coli B were prepared by incubating early log-phase cells in appropriate buffers and stabilizers for 3 hr at 30 and 37 C, respectively. Upon incubation in 0.05 m tris(hydroxymethyl)aminomethane buffer osmotically stabilized with 16% polyethylene glycol at pH 7.5, 99% of the B. cereus cells formed spheroplasts; 90% of the E. coli cells were converted to spheroplasts in 0.4 m sodium acetate buffer osmotically stabilized with 1.6 m sucrose at pH 6.0. The extent of spheroplast formation was determined by phase-contrast microscopic examination, by measuring the rate of fall of optical density in the reaction mixture when subjected to osmotic shock, and by viable intact cell counts. The effect of a selected group of metabolic inhibitors on the autolytic system of B. cereus and E. coli has been examined. B. cereus and E. coli wall components comprising 26% of the dry weight of the original cellular material were recovered from dialyzed fractions by precipitation in 70% ethyl alcohol. Chemical and chromatographic analysis of cell-wall hydrolysates from B. cereus and E. coli indicated the presence of glucosamine, alanine, lysine, glycine, aspartic acid, diaminopimelic acid, glutamic acid, and muramic acid.

Amino Acids↗
PubMed1975

Isolation and chemical characterization of outer envelope of Leptospira pomona.

Cells of Leptospira interrogans serotype pomona harvested from a chemically defined medium were resuspended in 0.01 M phosphate buffer of pH 7.3. Electron microscopy showed that 90 min of exposure effectively ruptured the outer envelope, freeing it from the cells as small flakes. Both zonal centrifugation in sucrose gradients and centrifugation in isopycnic KBr and CsCl gradients could be used to separate the outer envelope from the axial filaments and protoplasmic cylinders. The latter method resulting in higher yields of purified envelope with the particular protocols used. Thin sections of isolated outer envelope showed the same trilaminar structure seen in sections of intact cells. The outer layers were 1.5 nm thick and appeared as single layers of electron-dense particles. The central electron-transparent layer was 2.0-2.5 nm thick and appeared structureless. The gross chemical composition of the purified outer envelope was 47% protein, 27% carbohydrate, and 23% lipid. Colorimetric carbohydrate determinations revealed hexose, pentose, and 6-deoxyhexose; hexosamine was identified during amino acid analysis. Muramic acid, heptose, and 2-keto-3-deoxyoctonate were not detected. Thin-layer chromatography revealed only polar lipids, about 98% phosphatidylethanolamine and 2% lysophosphatidylethanolamine. Fatty acids identified by gas-liquid chromatography were octadecanoic, octadecenoic, hexadecanoic, and hexadecenoic. Amino acid analysis revealed 17 amino acids, histidine and glutamic acid being most abundant. The outer envelope was interpreted to be comparable with the outer double-track layer found in the cell covering of gram-negative eubacteria.

Amino Acids↗
PubMed1982

The composition of sleep-promoting factor isolated from human urine.

A sleep-promoting substance, Factor S, has been extracted and purified from large volumes of human urine. Urinary Factor S is a small glycopeptide; amino acid-amino sugar analyses of the purified material revealed a substance composed of glutamic acid, alanine, diaminopimelic acid, and muramic acid in molar ratios of 2:2:1:1. The active glycopeptide resembles bacterial peptidoglycans but the composition suggests that it is not simply of adventitious origin. Other reasons for this conclusion are also given. Infusions into the lateral ventricle of the brain of about 5 pmol/kg of body weight induce a 50% increase in slow wave sleep in rabbits. The excess sleep is normal as judged by electrophysiological and behavioral criteria; it resembles the deep sleep that occurs when animals are allowed to sleep following prolonged sleep deprivation.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed2004

Zimmermannella helvola gen. nov., sp. nov., Zimmermannella alba sp. nov., Zimmermannella bifida sp. nov., Zimmermannella faecalis sp. nov. and Leucobacter albus sp. nov., novel members of the family Microbacteriaceae.

Seven strains of actinobacteria, isolated from soil, wounds, urine, cow faeces, human blood and butter, were characterized by a polyphasic approach to clarify their taxonomic position. On the basis of chemotaxonomy, 16S rRNA gene analysis and DNA relatedness, strain IAM 14851T can be classified within the cluster of the genus Leucobacter and is proposed as a novel species, Leucobacter albus sp. nov., with strain IAM 14851T (=TISTR 1515T) as the type strain. The other six strains formed a phylogenetically separate branch in the family Microbacteriaceae, having the following characteristics: the major menaquinones are MK-8 to MK-10, the DNA G + C content ranges from 62 to 68 mol%, the diamino acid in the cell wall is diaminobutyric acid and the muramic acid in the peptidoglycan is of the acetyl type. The major fatty acids are 12-methyltetradecanoic acid (anteiso-C(15 : 0)), hexadecanoic acid (C(16 : 0)), 14-methyl-pentadecanoic acid (iso-C(16 : 0)) and 14-methyl-hexadecanoic acid (anteiso-C(17 : 0)). On the basis of morphological, physiological and chemotaxonomic characteristics, together with DNA-DNA hybridization and 16S rRNA gene sequence comparison, the novel genus Zimmermannella gen. nov. is proposed for these six strains. Four novel species are proposed: Zimmermannella helvola sp. nov. (type species; type strain IAM 14726T = NBRC 15775T = DSM 20419T = TISTR 1509T), Zimmermannella alba sp. nov. (type strain IAM 14724T = NBRC 15616T = TISTR 1510T), Zimmermannella bifida sp. nov. (type strain IAM 14848T = TISTR 1511T) and Zimmermannella faecalis sp. nov. (type strain IAM 15030T = NBRC 15706T = ATCC 13722T = TISTR 1514T).

Actinomycetales↗
PubMed1977

The structure of the branching point between acidic polysaccharide and peptidoglycan in Micrococcus lysodeikticus cell wall.

An acidic polysaccharide fraction composed of glucose and N-acetylmannosaminuronic acid with a small portion of peptidoglycan was isolated by enzymic digestion and subsequent ECTEOLA-cellulose chromatography from the cell walls of Micrococcus lysodeikticus. On mild acid treatment, the fraction became Morgan-Elson positive and formed the Morgan-Elson chromogen on heating with phosphate buffer (pH 7). The product of mild acid treatment released inorganic phosphate on treatment with phosphomonoesterase. After gel-chromatography on Sephadex G-25 and DE-32, the acidic polysaccharide fraction contained less glucosamine than muramic acid. By reduction of this fraction with borohydride, a part of the glucosamine was converted into glucosaminitol. Based on these results, it is suggested that the acidic polysaccharide is linked to glucosamine by a (1-3) linkage, which is linked to the 6 position of a muramic acid residue by a phosphodiester linkage.

Amino Acids↗
PubMed1994

Interaction of a legume lectin with two components of the bacterial cell wall. A crystallographic study.

We describe herein the refined high resolution x-ray structures of two components of the bacterial cell wall, muramic acid and muramyl dipeptide complexed to isolectin I from Lathyrus ochrus seeds. In both complexes, only the ring hydroxyl oxygen atoms of the bound sugar establish direct hydrogen bonds with isolectin I, as in the case of all the previously determined monosaccharide-lectin complexes. In addition, the lactyl methyl of both components strongly interacts via hydrophobic contacts with the side chains of residues Tyr100 and Trp128 of isolectin I, which could explain the higher affinity of isolectin I for muramic acid as compared with glucose. These 2 residues, however, are not involved in the stabilization of the oligosaccharide-isolectin I complexes. The dipeptide (D-Ala-D-iGln) of the second component is in stacking interaction with the N-acetyl group of glucose and with loop Gly97-Gly98 of isolectin I. In addition to these van der Waals' contacts, the dipeptide interacts with the lectin via well ordered water molecules also. Superposition of the structures of the muramyl dipeptide complex and of the muramic acid complex shows that the glucose ring in the dipeptide compound is tilted by about 15 degrees in comparison with that of muramic acid. The fact that the lactyl group has the same confrontation in both components reveals that the lectin is stereospecific and recognizes only diastereoisomer S of this group, which better fits the saccharide-binding site.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed2003

Characterization of LytH, a differentiation-associated peptidoglycan hydrolase of Bacillus subtilis involved in endospore cortex maturation.

The cortex peptidoglycan from endospores of Bacillus subtilis is responsible for the maintenance of dormancy. LytH (YunA) has been identified as a novel sporulation-specific component with a role in cortex structure determination. The lytH gene was expressed only during sporulation, under the control of the mother cell-specific sigma factor sigma(K). Spores of a lytH mutant have slightly reduced heat resistance and altered staining when viewed by electron microscopy. Analysis of the peptidoglycan structure of lytH mutant spores shows the loss of muramic acid residues substituted with L-alanine and a corresponding increase in muramic acid residues substituted with tetrapeptide compared to those in the parent strain. In a lytH cwlD mutant, the lack of muramic acid residues substituted with L-alanine and delta-lactam leaves 97% of residues substituted with tetrapeptide. These results suggest that lytH encodes an L-Ala-D-Glu peptidase involved in production of single L-alanine side chains from tetrapeptides in the spore cortex. The lack of di- or tripeptides in a lytH mutant reveals the enzyme is an endopeptidase.

Bacillus subtilis↗
PubMed1983

The sulfated polysaccharide-peptidoglycan complex from an Arthrobacter species: characterization of the linkage between the two components.

Further structural features of the sulfated polysaccharide-peptidoglycan complex, which is produced by an Arthrobacter sp. and contains phosphorus as its minor component, were investigated. Phosphoric acid esters such as D-glucose 6-phosphate, glycerol 1-phosphate and muramic acid phosphate were isolated from the acid hydrolysate of the complex. On mild acid treatment, the complex became positive for both the Morgan-Elson reaction and acid phosphatase digestion. The mild acid hydrolysate readily formed the Morgan-Elson chromogen on heating at pH 7, indicating release of terminal reducing N-acetylglucosamine substituted on C-3 by adjacent sugars, and its release was accompanied by that of phosphomonoester. The complex released peptidoglycan fragments on the mild acid treatment, together with acid-degraded, sulfated polysaccharide chains with terminal reducing N-acetylglucosamine. A large proportion of phosphorus in the complex was shown to occur in the sulfated polysaccharide chains, and the rest as muramic acid phosphate in the peptidoglycan fragments. After mild acid treatment of the complex, 50% of total phosphorus was released as inorganic phosphate on phosphatase digestion of the hydrolysate. These results suggest that the sulfated polysaccharide chains, which are additionally phosphorylated to a low degree, are linked to the peptidoglycan fragments through acid-labile phosphodiester linkages, probably between (1 leads to 3)-linked N-acetylglucosamine 1-phosphate and muramic acid.

Arthrobacter↗
PubMed1971

Structure of the cell wall of Bacillus stearothermophiluys: mode of action of a thermophilic bacteriophage lytic enzyme.

The mode of action of a bacteriophage lytic enzyme on cell walls of Bacillus stearothermophilus (NCA 1503-4R) has been investigated. The enzyme is an endopeptidase which catalyzes the hydrolysis of the l-alanyl-d-glutamyl linkage in peptide subunits of the cell wall peptidoglycan. Preliminary studies on the soluble components in lytic cell wall digests indicate that the glycan moiety is composed of alternating glucosamine and muramic acid; one half of the muramic acid residues contain the tripeptide, l-alanyl-d-glutamyldiaminopimelic acid, and the remaining residues contain the tetrapeptide, l-alanyl-d-glutamyldiaminopimeyl-d-alanine. Almost one half of the peptide subunits are involved in cross-linkages of chemotype I. A structure for the cell wall peptidoglycan is proposed in the light of these findings.

Alanine↗
PubMed1991

Rapid elimination of a synthetic adjuvant peptide from the circulation after systemic administration and absence of detectable natural muramyl peptides in normal serum at current analytical limits.

Although it is clear that muramyl peptides are involved in sleep associated with bacterial infection, their role in normal physiological sleep is less certain. It has been speculated that "natural" muramyl peptides, derived from degraded gut flora, may pass into the bloodstream, where they play a role in normal sleep (M. Karnovsky, Fed. Proc. 45:2556-2560, 1986). Muramic acid serves as a chemical marker for muramyl peptides, since it is not synthesized by mammals. After injection of synthetic muramyl dipeptide in rabbits, muramic acid was readily detected (after release by acid hydrolysis) in the circulation; however, levels rapidly decreased. This was an important positive control in assessing circulating levels of natural muramyl peptides. Muramic acid was not found in normal serum (detection limit, approximately 500 pmol/ml), demonstrating the absence of appreciable amounts of circulating natural muramyl peptides. At this time we are unable to provide supportive evidence for Karnovsky's hypothesis.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1969

L'acide N-glycolyl-muramique, constituant des parois de Mycobacterium smegmatis: Identification par spectrometrie de masse.

The repeating disaccharide unit of the mucopeptide of the cell wall of Mycobacterium smegmatis contains N-acetyl-glucosamine linked to N-glycolyl-muramic acid. This first identification of N-glycolyl-muramic acid as a natural product has been performed by mass spectrometry of the permethylated disaccharide. N-glycolyl muramic acid has been synthesized: the natural and synthetic products are identical.

Journal Article↗
PubMed1973

Amino acid sequence of the threonine-containing mureins of coryneform bacteria.

In a study of the mureins of coryneform bacteria (Arthrobacter, Brevibacterium, Cellulomonas, Corynebacterium, Erysipelothrix), 21 threonine-containing strains were found. In several of the strains the amino acid and amino sugar composition of the murein was muramic acid (Mur), glucosamine (GlcNH(2)), d-Glu, l-Lys, l-Thr, and Ala in a molar ratio of 1:1:1:1:1:4 or 5, and in several other strains it was Mur, GlcNH(2), d-Glu, l-Lys, l-Thr, Ala, and l-Ser in a molar ratio of 1:1:1:1:1:3:1. The amino acid sequence of the mureins was determined by analyzing the oligopeptides derived from partial acid hydrolysates. It was shown that there were five different murein types. The peptide subunits attached to the muramic acid are the same, namely l-Ala-d-GluNH(2)-l-Lys-d-Ala. In one strain, the alpha-carboxyl group of d-Glu is substituted by d-alanine amide. The interpeptide bridges of the different types consist of the peptides l-Ala-l-Thr-l-Ala, l-Ala-l-Thr, l-Ala-l-Ala-l-Thr, l-Ala-l-Ala-l-Ala-l-Thr, or l-Ala-l-Thr-l-Ser which are bound through their C-termini (l-Ala, l-Thr, l-Ser) to the epsilon-amino group of l-Lys of one peptide subunit and by their N-termini (l-Ala) to the C-terminal d-Ala of an adjacent peptide subunit. Determination of the N- and C-terminal groups in the mureins showed that about 15 to 30% of the interpeptide bridges are not cross-linked.

Amino Acid Sequence↗
PubMed1999

The role of peptidoglycan structure and structural dynamics during endospore dormancy and germination.

Dormant, bacterial endospores are the most resistant living structures known. The spore cell wall (cortex) maintains dormancy, core dehydration, and heat resistance. The cortex peptidoglycan has a unique, spore specific structure that enables it to fulfill its role. The cross-linking index of spore cortex peptidoglycan is very low, occurring at only 2.9% of the muramic acid residues compared to 33% in vegetative cells. The level of cross-linking of the cortex may be important in maintaining spore dormancy and heat resistance. Approximately 50% of the muramic acid residues in spore cortex are substituted with muramic delta-lactam. This modification is spore specific and is the major characteristic feature of the cortex. The muramic delta-lactam has no apparent role in establishing core dehydration, maintaining dormancy or heat resistance. However, the muramic delta-lactam residues are necessary for spore cortex hydrolysis during germination. They constitute part of the substrate recognition profile of the germination specific lytic enzymes (GSLEs) which are responsible for cortex hydrolysis. Germination results in loss of dormant spore properties and hydrolysis of the cortex is essential for later germination events and outgrowth. Application of muropeptide analysis to determine peptidoglycan structural dynamics during germination has revealed an unexpected degree of complexity in peptidoglycan hydrolysis. At least three hydrolytic activities, an N-acetyl glucosaminidase, a lytic transglycosylase and a possible amidase, are involved. A non-hydrolytic activity, likely to be an epimerase of muramic acid also occurs early during germination. The lytic transglycosylase generates anhydro-muropeptides which are released during germination and may be recycled during outgrowth to form part of the new vegetative cell wall.

Bacillus subtilis↗