Lactic Acid Resistance and Population Structure of Escherichia coli from Meat Processing Environment

To explore the effect of beef processing on Escherichia coli populations in relation to lactic acid resistance, this study investigated the links among acid response, phylogenetic structure, genome diversity, and genotypes associated with acid resistance of meat plant E. coli. Generic E. coli isolates (n = 700) were from carcasses, fabrication equipment, and beef products. Acid treatment was carried out in Luria-Bertani broth containing 5.5% lactic acid (pH 2.9). Log reductions of E. coli ranged from <0.5 to >5 log CFU/mL (median: 1.37 log). No difference in lactic acid resistance was observed between E. coli populations recovered before and after a processing step or antimicrobial interventions. E. coli from the preintervention carcasses were slightly more resistant than E. coli isolated from equipment, differing by <0.5 log unit. Acid-resistant E. coli (log reduction <1, n = 45) had a higher prevalence of genes related to energy metabolism (ydj, xap, ato) and oxidative stress (fec, ymjC) than the less resistant E. coli (log reduction >1, n = 133). The ydj and ato operons were abundant in E. coli from preintervention carcasses. In contrast, fec genes were abundant in E. coli from equipment surfaces. The preintervention E. coli contained phylogroups A and B1 in relatively equal proportions. Phylogroup B1 predominated (95%) in the population from equipment. Of note, E. coli collected after sanitation shared either the antigens of O8 or H21. Additionally, genome diversity decreased after chilling and equipment sanitation. Overall, beef processing did not select for E. coli resistant to lactic acid but shaped the population structure. IMPORTANCE Antimicrobial interventions have significantly reduced the microbial loads on carcasses/meat products; however, the wide use of chemical and physical biocides has raised concerns over their potential for selecting resistant populations in the beef processing environment. Phenotyping of acid resistance and whole-genome analysis described in this study demonstrated beef processing practices led to differences in acid resistance, genotype, and population structure between carcass- and equipment-associated E. coli but did not select for the acid-resistant population. Results indicate that genes coding for the metabolism of long-chain sugar acids (ydj) and short-chain fatty acids (ato) were more prevalent in carcass-associated than equipment-associated E. coli. These results suggest E. coli from carcasses and equipment surfaces have been exposed to different selective pressures. The findings improve our understanding of the microbial ecology of E. coli in food processing environments and in general.

Discriminant ability of phenolic compounds and short chain organic acids profiles in the determination of quality parameters of Brandy de Jerez

Brandy de Jerez is the most produced spirit in Spain. The rules of its Regulatory Council require the spirit to age in American oak casks that have previously contained any kind of sherry wine. This use, called seasoning, releases wine compounds into the spirit. Because of the differences among sherries, the organoleptic features of a brandy will be significantly different from any other depending on the seasoning. In addition, its specific features make it different from any other spirit. The chromatographic profiles of Brandy de Jerez are reported to be different depending on the seasonings through their ageing process. Different types of Brandy de Jerez have been characterised, regarding their seasoning, using chromatographic techniques. Applying statistical analysis, correlations between the chromatographic profiles and the seasonings have risen up. In addition, the profiles have demonstrated to possess a high degree of correlation with the ageing time of the samples.

Characterization of the Kingella kingae polysaccharide capsule and exopolysaccharide

Recent evidence indicates that Kingella kingae produces a polysaccharide capsule. In an effort to determine the composition and structure of this polysaccharide capsule, in the current study we purified capsular material from the surface of K. kingae strain 269-492 variant KK01 using acidic conditions to release the capsule and a series of steps to remove DNA, RNA, and protein. Analysis of the resulting material by gas chromatography and mass spectrometry revealed N-acetyl galactosamine (GalNAc), 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo), and galactose (Gal). Further analysis by NMR demonstrated two distinct polysaccharides, one consisting of GalNAc and Kdo with the structure →3)-β-GalpNAc-(1→5)-β-Kdop-(2→ and the other containing galactose alone with the structure →5)-β-Galf-(1→. Disruption of the ctrA gene required for surface localization of the K. kingae polysaccharide capsule resulted in elimination of GalNAc and Kdo but had no effect on the presence of Gal in bacterial surface extracts. In contrast, deletion of the pamABCDE locus involved in production of a reported galactan exopolysaccharide eliminated Gal but had no effect on the presence of GalNAc and Kdo in surface extracts. Disruption of ctrA and deletion of pamABCDE resulted in a loss of all carbohydrates in surface extracts. These results establish that K. kingae strain KK01 produces a polysaccharide capsule with the structure →3)-β-GalpNAc-(1→5)-β-Kdop-(2→ and a separate exopolysaccharide with the structure →5)-β-Galf-(1→. The polysaccharide capsule and the exopolysaccharide require distinct genetic loci for surface localization.

Simulation and prediction of the thuringiensin abiotic degradation processes in aqueous solution by a radius basis function neural network model

The thuringiensin abiotic degradation processes in aqueous solution under different conditions, with a pH range of 5.0-9.0 and a temperature range of 10-40°C, were systematically investigated by an exponential decay model and a radius basis function (RBF) neural network model, respectively. The half-lives of thuringiensin calculated by the exponential decay model ranged from 2.72 d to 16.19 d under the different conditions mentioned above. Furthermore, an RBF model with accuracy of 0.1 and SPREAD value 5 was employed to model the degradation processes. The results showed that the model could simulate and predict the degradation processes well. Both the half-lives and the prediction data showed that thuringiensin was an easily degradable antibiotic, which could be an important factor in the evaluation of its safety.

Enhancement of 2-keto-gulonic acid yield by serial subcultivation of co-cultures of Bacillus cereus and Ketogulonicigenium vulgare

The co-cultures of Ketogulonicigenium vulgare and Bacillus cereus were subcultured daily for a total of 150 transfers. The yield of 2-keto-gulonic acid (2-KGA) and medium pH in the co-cultures were measured. We found that the serial subcultivation increased the yield of 2-KGA from 77% (original co-culture) to 93% (the 150th transfer of transferred co-culture). The resulted strains are of industrial interests for vitamin C production.

Root exudation of phytochemicals in Arabidopsis follows specific patterns that are developmentally programmed and correlate with soil microbial functions

Plant roots constantly secrete compounds into the soil to interact with neighboring organisms presumably to gain certain functional advantages at different stages of development. Accordingly, it has been hypothesized that the phytochemical composition present in the root exudates changes over the course of the lifespan of a plant. Here, root exudates of in vitro grown Arabidopsis plants were collected at different developmental stages and analyzed using GC-MS. Principle component analysis revealed that the composition of root exudates varied at each developmental stage. Cumulative secretion levels of sugars and sugar alcohols were higher in early time points and decreased through development. In contrast, the cumulative secretion levels of amino acids and phenolics increased over time. The expression in roots of genes involved in biosynthesis and transportation of compounds represented in the root exudates were consistent with patterns of root exudation. Correlation analyses were performed of the in vitro root exudation patterns with the functional capacity of the rhizosphere microbiome to metabolize these compounds at different developmental stages of Arabidopsis grown in natural soils. Pyrosequencing of rhizosphere mRNA revealed strong correlations (p<0.05) between microbial functional genes involved in the metabolism of carbohydrates, amino acids and secondary metabolites with the corresponding compounds released by the roots at particular stages of plant development. In summary, our results suggest that the root exudation process of phytochemicals follows a developmental pattern that is genetically programmed.

Nonvolatile oxidation products of glucose in Maillard model systems: formation of saccharinic and aldonic acids and their corresponding lactones

By using pyrolysis-gas chromatography-mass spectrometry-based methodologies, nonvolatile oxidation products of isotopically labeled glucose/glycine model systems were studied through a postpyrolytic in situ derivatization technique by using trimethylsilyldiethylamine. Analysis of the data indicated that the known reactive sugar intermediates such as glucosone and its deoxy derivatives can undergo in Maillard model systems three types of transformations: oxidation of the aldehydic groups into carboxylic acids, oxidative cleavage of alpha-dicarbonyl moieties into aldonic acids, and benzylic acid rearrangement of 1-deoxy-glucosone into saccharinic acids. The aldonic and saccharinic acids were identified through silylation of their lactone derivatives, and their origin was verified through (13)C-labeling studies. The following lactones were identified in glucose and glucose/glycine model systems: trans-dihydro-3,4-bis[(trimethylsilyl)oxy]-2(3 H)-furanone, cis-dihydro-3,4-bis[(trimethylsilyl)oxy]-2(3H)-furanone, 2-C-methyl-2,3,5-tris-O-(trimethylsilyl)-D-ribonic acid gamma-lactone, 3-deoxy-2,5,6-tris-O-(trimethylsilyl)-D-ribo-hexonic acid gamma-lactone, 2-deoxy-3,5-bis-O-(trimethylsilyl)-pentonic acid gamma-lactone, and 2,3,5-tris-O-(trimethylsilyl)-D-arabinonic acid gamma-lactone. The observed reduction in color and aroma in Maillard reactions performed under oxidative conditions may be attributed to the oxidation of reactive dicarbonyls into the corresponding carboxylic acids or their corresponding lactones.

Capillary electrophoresis of sugar acids

This chapter illustrates the usefulness of capillary electrophoresis (CE) for the analysis of sugar acids, that is, monosaccharides and lower oligosaccharides carrying carboxylate, sulphate or phosphate groups. In order to provide a general description of the main results and challenges in the field, some relevant applications and reviews on CE of such saccharidic compounds are tabulated. Furthermore, some detailed experimental procedures are shown, regarding the CE analysis of sugar acids released upon hydrolysis of acidic polysaccharides and of glycans linked to glycoproteins. In particular, the protocols will deal with the following compounds: (i) unsaturated, underivatized oligosaccharides from lyase-treated alginate; (ii) oligosaccharides derivatized with 4-aminobenzonitrile, arising from chemical hydrolysis of alginate; (iii) sialic acid derivatized with 2-aminoacridone, released from human serum immunoglobulin G.

Reactivity of 2'-deoxyuridin-1'-yl radical in various DNA structures

DNA C1' radicals formed by hydrogen atom abstraction from the C1' position of the sugar backbone lead to the production of 2'-deoxyribonolactone as a DNA damage lesion. Although DNA C1' radicals may be involved in a variety of DNA damage processes, there is very little information on the molecular basis of DNA structure dependence in the reactions of C1' radicals. Here, we describe a detailed study of the reactivity of 2'-deoxyuridin-1'-yl radicals in single- and double-stranded B-form DNA and G-quartets in the formation of 2'-deoxyribonolactone, using the unnatural precursor 1'-pivaloyl-2'-deoxyuridine (1).

A new polymer of 8,9-Di-O-Glucosylated 2-keto-3-deoxy-D-glycero-D-galacto-nonulosonic acid from a cell wall of Brevibacterium casei ACM Ac-2114T

A polysaccharide containing the residues of 2-keto-3-deoxy-D-glycero-D-galacto-nonulosonic acid (Kdn) was found in the cell wall of the Brevibacterium casei strain AEI Ac-2114T . The polymer structure was elucidated by analyzing one-dimensional spectra of 1H and 13C NMR and bidimentional experiments 1H/13C-COSY, TOCSY, 1H/13C-gHSQC, and 1H/13C-gHMBC. The polymer is built up of the 2--> 4-linked Kdn residues substituted by beta-D-Glcp residues at 8- and 9-hydroxyls; such a polymer with disubstituted Kdn residues was found for the first time. A glycosylated teichoic acid of the 1,3-poly(glycerophosphate) type was also identified among other anionic polymers of cell wall.

The structure of the O-polysaccharide from the lipopolysaccharide of Providencia alcalifaciens O36 containing 3-deoxy-d-manno-oct-2-ulosonic acid

An oligosaccharide that corresponds to the repeating unit of the O-polysaccharide was obtained by mild acid degradation of the lipopolysaccharide of Providencia alcalifaciens O36. Structural studies of the oligosaccharide and O-deacylated lipopolysaccharide were performed using sugar and methylation analyses along with (1)H and (13)C NMR spectroscopy, including 2D (1)H,(1)H COSY, TOCSY, ROESY, and H-detected (1)H,(13)C HSQC and HMBC experiments. It was found that the O-polysaccharide is built up of linear trisaccharide repeating units containing 2-acetamido-2-deoxyglucose, 6-deoxy-l-talose (l-6dTal), and 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) and has the following structure. [structure: see text]

Micromethods for the characterization of lipid A-core and O-antigen lipopolysaccharide

Methods for rapid and simple analysis of lipopolysaccharide (LPS) from bacterial whole-cell lysates or membrane preparations have contributed to advancing our knowledge of the genetics of the LPS biogenesis. LPS, a major constituent of the outer membranes in Gram-negative bacteria, has a complex mechanism of synthesis and assembly that requires the coordinated participation of many genes and gene products. This chapter describes a collection of methods routinely used in our laboratory for the characterization of LPS in Escherichia coli and other bacteria.

Sialic acid concentrations in plants are in the range of inadvertent contamination

The long held but challenged view that plants do not synthesize sialic acids was re-evaluated using two different procedures to isolate putative sialic acid containing material from plant tissues and cells. The extracts were reacted with 1,2-diamino-4,5-methylene dioxybenzene and the fluorescently labelled 2-keto sugar acids analysed by reversed phase and normal phase HPLC and by HPLC-electrospray tandem mass spectrometry. No N-glycolylneuraminic acid was found in the protein fraction from Arabidopsis thaliana MM2d cells. However, we did detect 3-deoxy-D: -manno-octulosonic acid and trace amounts (3-18 pmol/g fresh weight) of a compound indistinguishable from N-acetylneuraminic acid by its retention time and its mass spectral fragmentation pattern. Thus, plant cells and tissues contain five orders of magnitude less sialic acid than mammalian tissues such as porcine liver. Similar or lower amounts of N-acetylneuraminic acid were detected in tobacco cells, mung bean sprouts, apple and banana. Yet even yeast and buffer blanks, when subjected to the same isolation procedures, apparently contained the equivalent of 5 pmol of sialic acid per gram of material. Thus, we conclude that it is not possible to demonstrate unequivocally that plants synthesize sialic acids because the amounts of these sugars detected in plant cells and tissues are so small that they may originate from extraneous contaminants.

Determination of endotoxin by the measurement of the acetylated methyl glycoside derivative of Kdo with gas–liquid chromatography-mass spectrometry

A gas-liquid chromatographic-mass spectrometric (GLC-MS) method was applied to the detection of 3-deoxy-d-manno-2-octulosonic acid (Kdo), a constituent of bacterial lipopolysaccharide (LPS, endotoxin). Samples containing LPS were dried, methanolyzed with 2 M HCl in methanol at 60 degrees C for 1 h and acetylated with acetic anhydride and pyridine (1:1, v/v) solution at 100 degrees C for 30 min, then the products were analyzed by GLC-MS or GLC-MSMS. Four acetylated methylglycoside methyl ester derivatives of Kdo are formed in these conditions, namely one with pyranose ring (Kdo1), two derivatives in the furanose form (Kdo2 and 3) and one derivative of anhydro Kdo (Kdo4), as results from their mass fragmentation patterns. Synthetic Kdo produced mainly Kdo4 derivative, whereas Kdo1 of pyranose ring shape was the predominating derivative formed from LPS. The ion fragment of m/z 375 was selected for the specific detection of this Kdo1 derivative, which might be applied for the endotoxin determination. That approach was used for the analysis of preparations of bacteria, bacteriophages and samples of animal sera. In order to ensure the removal of phosphate substitutions from Kdo, methanolyzed samples can be treated with alkaline phosphatase (2.6 U, pH 9.2, 37 degrees C, 15 min), what was elaborated on Vibrio LPS preparation.

Roles of 3-deoxy-D-manno-2-octulosonic acid transferase from Moraxella catarrhalis in lipooligosaccharide biosynthesis and virulence

Lipooligosaccharide (LOS), a major outer membrane component of Moraxella catarrhalis, is a possible virulence factor in the pathogenesis of human infections caused by the organism. However, information about the roles of the oligosaccharide chain from LOS in bacterial infection remains limited. Here, a kdtA gene encoding 3-deoxy-D-manno-2-octulosonic acid (Kdo) transferase, which is responsible for adding Kdo residues to the lipid A portion of the LOS, was identified by transposon mutagenesis and construction of an isogenic kdtA mutant in strain O35E. The resulting O35EkdtA mutant produced only lipid A without any core oligosaccharide, and it was viable. Physicochemical and biological analysis revealed that the mutant was susceptible to hydrophobic reagents and a hydrophilic glycopeptide and was sensitive to bactericidal activity of normal human serum. Importantly, the mutant showed decreased toxicity by the Limulus amebocyte lysate assay, reduced adherence to human epithelial cells, and enhanced clearance in lungs and nasopharynx in a mouse aerosol challenge model. These data suggest that the oligosaccharide moiety of the LOS is important for the biological activity of the LOS and the virulence capability of the bacteria in vitro and in vivo. This study may bring new insights into novel vaccines or therapeutic interventions against M. catarrhalis infections.

Selective detection of 2-deoxyribonolactone in DNA

2-Deoxyribonolactone (L) is an oxidized abasic lesion that is produced by a variety of DNA damaging agents. It exhibits unique biological effects with respect to its proclivity to form DNA-protein cross-links and promutagenic base pairs. Recent evidence suggests that the levels of this lesion caused by oxidative stress are underestimated. We have developed a simple, selective method for detecting subpicomole amounts of L in DNA. The method takes advantage of the selective reaction of the butenolide (2) derived from beta-elimination from L with a biotinylated derivative of cysteine. This method will be useful for analyzing the levels of this oxidized abasic site in DNA.

Organic matter released from activated sludge bacteria cells during their decay process

Organic matter released from activated sludge bacteria is a considerable issue in the wastewater reclamation process. In this study, we focused 2-keto-3-deoxyoctulosonic acid in the Lipopolysaccharide existed in the gram-negative bacterial cell wall as an index of organic matter released from bacteria, and investigated the fate of 2-keto-3-deoxyoctulosonic acid in the aerated and ultrasonicated activated sludge samples. The results shows 1) 2-keto-3-deoxyoctulosonic acid concentration in the hydrolyzed sample was higher than non-hydrolyzed sample, and this implied that 2-keto-3-deoxyoctulosonic acid existed in the water phase as a monomer and also as a polymer such as Lipopolysaccharide form and their fragments; 2) the value of (2-keto-3-deoxyoctulosonic acid)/(dissolved organic carbon) ratio did not change in the sludge sonication process and was approximately 0.0006, on the other hand, in the bacteria decay process, the ratio varied from zero to approximately 0.0012; 3) the linear relationship was observed between the degraded heterotrophic biomass and the generated 2-keto-3-deoxyoctulosonic acid; and 4) 2-keto-3-deoxyoctulosonic acid might be considered as an index of organic matter originated from activated sludge bacteria cell.

Fluorescent chemosensors for carbohydrates: a decade's worth of bright spies for saccharides in review

This review provides a chronological survey of over fifty fluorescent chemosensors for carbohydrates from the period between 1992 to the present. The survey contains only those sensors that are synthetic or chemosensory, utilize boronic acids and display a fluorescence response in the form of intensity changes or shifts in wavelength. With each compound listed, a description of the saccharide probe is given with regard to concentration, excitation and emission wavelengths, pH and solvent mixture proportions. In addition, the selectivity of each chemosensor is provided as well as the trends in binding constants. Where possible, a description of the fluorescence signaling mechanism is given as well as commentary on the probe's unique features within this class of sensors.

An Enantioselective Fluorescent Sensor for Sugar Acids

Chiral fluorescent boronic acid 1 was found to be a highly enantioselective, chemoselective, and sensitive sensor for sugar acids, such as tartaric acid. Enantioselectivities (K(R)/K(S)) of up to 550:1, chemoselectivity up to 11,000:1, and sensitivities in the micromolar range with sensor 1 were observed. Single-crystal X-ray analysis was used to confirm the structure of the fluorescent species.

The structure of the core region of the lipopolysaccharide from Shewanella algae BrY, containing 8-amino-3,8-dideoxy-D-manno-oct-2-ulosonic acid

The structure of the carbohydrate backbone of the lipid A-core region of the LPS from Shewanella algae strain BrY was analysed. The LPS was N,O-deacylated to give three products, which were isolated and studied by chemical methods, NMR and mass spectrometry: [Carbohydrate structures: see text]. All monosaccharides except L-rhamnose had the D-configuration. This LPS presents a second example (after S. oneidensis) of the structure with a novel linking unit between the core and lipid A moieties, 8-amino-3,8-dideoxy-D-manno-oct-2-ulosonic acid (8-amino-Kdo).

Screening of the insecticidal activity of Bacillus thuringiensis strains against Lygus hesperus (Hemiptera: Miridae) nymphal population

Lygus hesperus Knight (Hemiptera: Miridae) is an economically important insect pest controlled primarily by chemical pesticides. Bacillus thuringiensis Berliner is a gram-positive bacterium that has been developed for the control of some insect pests in the orders Lepidoptera, Coleoptera, and Diptera. In this study, whole culture extracts of 94 B. thuringiensis strains from 83 serovars were added to an artificial diet and assayed against L. hesperus first and second instars. A total of five B. thuringiensis strains, B. thuringiensis variety thuringiensis, thuringiensis exotoxin +, morrisoni, tolworthi, and darmstadiensis generated > 98% mortality after 7 d of incubation. The screening was repeated with 117 alkali-solubilized trypsin-digested B. thuringiensis cultures and the same five B. thuringiensis strains showed nearly identical results. All five strains produce beta-exotoxin, which exhibits a wide host spectrum activity. No beta-exotoxin-minus B. thuringiensis strains showed significant toxicity against L. hesperus nymphs. The present work is one of the first thorough screenings of the wide diversity of the B. thuringiensis varieties for the control of L. hesperus nymphal populations.

Occurrence and linkage between secreted insecticidal toxins in natural isolates of Bacillus thuringiensis

Little is known about the occurrence and linkage between secreted insecticidal virulence factors in natural populations of Bacillus thuringiensis (Bt). We carried out a survey of 392 Bt strains isolated from various samples originating from 31 countries. The toxicity profile of the culture supernatants of these strains was determined individually against Anthonomus grandis (Coleoptera) and Spodoptera littoralis (Lepidoptera). We analyzed beta-exotoxin I production and searched for the genes encoding Vip1-2, Vip3, and Cry1I toxins in 125 of these strains. Our results showed that these insecticidal toxins were widespread in Bt but that their distribution was nonrandom, with significant linkage observed between vip3 and cry1I and between vip1-2 and beta-exotoxin I. Strains producing significant amounts of beta-exotoxin I were more frequently isolated from invertebrate samples than from dust, water, soil, or plant samples.

Phase-variation of the truncated lipo-oligosaccharide of Neisseria meningitidis NMB phosphoglucomutase isogenic mutant NMB-R6

The detection of antibodies specific to meningococcal lipo-oligosaccharides (LOSs; outer-core-->inner-core-->lipid A) in sera of patients convalescent from meningococcal infection suggests the potential use of LOS as a vaccine to combat pathogenic Neisseria spp. Removal of the outer-core region, which expresses glycans homologous to human blood-group antigens, is a required first-step in order to avoid undesirable immunological reactions following vaccination. To this end, we describe here the structural makeup of the LOS produced by serogroup B N. meningitidis NMB isogenic phosphoglucomutase (Pgm) mutant (NMB-R6). The dominant LOS types produced by NMB-R6 expressed a deep-truncated inner-core region, GlcNAc-(1-->2)-LDHepII-(1-->3)-LDHepI-(1-->5)-[Kdo-2-->4]-Kdo-->lipid A, with one PEA unit attached at either O-6 or O-7 of LDHepII, or with two simultaneously PEA moieties attached at O-3 and O-6 or O-3 and O-7 of the same unit. Unexpectedly, this mutation did not completely deactivate the production of Glc, as some LOS molecules were observed to carry Glc at O-4 of LDHepI and at O-3 of LDHepII. A glycoconjugate vaccine comprised of NMB-R6 LOSs is currently being evaluated in our laboratory.

Structure of the lipopolysaccharide of Pseudomonas aeruginosa O-12 with a randomly O-acetylated core region

The lipopolysaccharide of Pseudomonas aeruginosa O-12 was studied by strong alkaline and mild acid degradations and dephosphorylation followed by fractionation of the products by GPC and high-performance anion-exchange chromatography and analyses by ESI FT-MS and NMR spectroscopy. The structures of the lipopolysaccharide core and the O-polysaccharide repeating unit were elucidated and the site and the configuration of the linkage between the O-polysaccharide and the core established. The core was found to be randomly O-acetylated, most O-acetyl groups being located on the terminal rhamnose residue of the outer core region.

Structure and serological characterization of 5,7-diamino-3,5,7,9-tetradeoxy-non-2-ulosonic acid isolated from lipopolysaccharides of Vibrio parahaemolyticus O2 and O-untypable strain KX-V212

Lipopolysaccharides (LPS) of Vibrio parahaemolyticus O2 and O-untypable (OUT) strain (KX-V212) isolated from an individual patient were shown to contain 5,7-diamino-3,5,7,9-tetradeoxy-non-2-ulosonic acid (NonlA), which was readily released from LPS by mild acid hydrolysis. In the present study, we investigated the chemical and serological properties of NonlA isolated from LPS of V. parahaemolyticus O2 and OUT KX-V212. GC-MS and NMR analysis identified the NonlA from LPS of O2 to be 5,7-diacetamido-3,5,7,9-tetradeoxy-D-glycero-D-galacto-non-2-ulosonic acid (5NAc7NAcNonlA) and that from LPS of KX-V212 to be 5-acetamido-7-(N-acetyl-D-alanyl)amido-3,5,7,9-tetradeoxy-D-glycero-D-galacto-non-2-ulosonic acid (5NAc7NAlaNAcNonlA). In ELISA inhibition analysis, 5NAc7NAcNonlA inhibited the O2 LPS/anti-O2 antiserum system, whereas, 5NAc7NAlaNAcNonlA did not show any inhibitory activity. However, after N-deacylation of 5NAc7NAlaNAcNonlA followed by N-acetylation, the product (5NAc7NAcNonlA) inhibited the O2 LPS/anti-O2 antiserum system to the same extent as that of 5NAc7NAcNonlA obtained from O2 LPS. These results suggest that 5NAc7NAcNonlA might be related to the serological specificity of O2 LPS as one of main epitope(s) involved in O2 LPS.

The use of thermal lensing for the determination of pyrogens

Based on the optimized spectrophotometric determination of pyrogens (of various classes ( p-aminophenol and endotoxins), thermal lensing was applied to the determination of these substances at the submicrogram level. The limit of detection of p-aminophenol, a pyrogenic impurity in pharmaceutical formulations of paracetamol, by reaction with resorcinol in alkaline solutions is 100 ng mL(-1). Phloroglucinol was considered as an analog of resorcinol as a reagent in this reaction. The conditions of spectrophotometric determination of pyrogenic lipopolysaccharides (endotoxins) by ion-pair formation with methylene blue (the limit of detection is 100 ng mL(-1)), by ion-pair formation with Stains-All (1-ethyl-2-[3-(1-ethylnaphtho[1,2-d]thiazolin-2-ylidene)-2-methylpropenyl]naphtho[1,2-d]thiazolium bromide) (the limit of detection is 500 ng mL(-1)), and by reaction of 2-keto-3-deoxyoctonic acid with thiobarbituric acid (the limit of detection is 800 ng mL(-1)) were proposed. The optimized procedure for 2-keto-3-deoxyoctonic acid was applied for thermal lensing that provided a decrease in the limit of detection to 70 ng mL(-1) and was also used for lipopolysaccharide determination in the endotoxin standard from E. coli.

Construction and application of a mass spectral and retention time index database generated from plant GC/EI-TOF-MS metabolite profiles

The non-supervised construction of a mass spectral and retention time index data base (MS/RI library) from a set of plant metabolic profiles covering major organs of potato (Solanum tuberosum), tobacco (Nicotiana tabaccum), and Arabidopsis thaliana, was demonstrated. Typically 300-500 mass spectral components with a signal to noise ratio > or =75 were obtained from GC/EI-time-of-flight (TOF)-MS metabolite profiles of methoxyaminated and trimethylsilylated extracts. Profiles from non-sample controls contained approximately 100 mass spectral components. A MS/RI library of 6205 mass spectral components was accumulated and applied to automated identification of the model compounds galactonic acid, a primary metabolite, and 3-caffeoylquinic acid, a secondary metabolite. Neither MS nor RI alone were sufficient for unequivocal identification of unknown mass spectral components. However library searches with single bait mass spectra of the respective reference substance allowed clear identification by mass spectral match and RI window. Moreover, the hit lists of mass spectral searches were demonstrated to comprise candidate components of highly similar chemical nature. The search for the model compound galactonic acid allowed identification of gluconic and gulonic acid among the top scoring mass spectral components. Equally successful was the exemplary search for 3-caffeoylquinic acid, which led to the identification of quinic acid and of the positional isomers, 4-caffeoylquinic acid, 5-caffeoylquinic acid among other still non-identified conjugates of caffeic and quinic acid. All identifications were verified by co-analysis of reference substances. Finally we applied hierarchical clustering to a complete set of pair-wise mass spectral comparisons of unknown components and reference substances with known chemical structure. We demonstrated that the resulting clustering tree depicted the chemical nature of the reference substances and that most of the nearest neighbours represented either identical components, as judged by co-elution, or conformational isomers exhibiting differential retention behaviour. Unknown components could be classified automatically by grouping with the respective branches and sub-branches of the clustering tree.

Diversity of the human erythrocyte membrane sialic acids in relation with blood groups

The composition of the human erythrocyte membrane (RBC) glycoprotein- and glycolipid-bound sialic acids of A, B, AB and O type donors was studied using a new method (Zanetta et al., Glycobiology 11 (2001) 663-676). In addition to Neu5Ac as the major compound, Kdn, Neu5,9Ac(2), Neu5,7Ac(2), Neu (de-N-acetylated-Neu5Ac), Neu5Ac8Me, Neu5Ac9Lt, Neu4,5Ac(2), Neu5,8Ac(2)9Lt and Neu5Ac8S were characterised. Among these different compounds, Neu5Ac8Me, Neu5Ac9Lt, Neu4,5Ac(2), Neu5,8Ac(2)9Lt and Neu5Ac8S have never been described and quantitatively determined before in human tissues or cells. Neu5Gc and its O-alkylated or O-acylated derivatives were not detected.

[Characterization of lipopolysaccharides from Ralstonia solanacearum]

Lipopolysaccharides (LPSs) from four strains of Ralstonia solanacearum belonging to biovar I (ICMP 6524, 8115, 5712, and 8169) were isolated and investigated. The structural components of the LPS molecule, such as lipid A, the core oligosaccharide, and O-specific polysaccharide (O-PS), were obtained after mild acid hydrolysis of the LPS preparations. In lipid A from all the LPS samples studied, 3-hydroxyhexadecanoic, 2-hydroxyhexadecanoic, tetradecanoic, and hexadecanoic fatty acids prevailed. The dominant monosaccharides of the core oligosaccharides of all of the strains studied were rhamnose, glucose, glucosamine, 2-keto-3-deoxyoctulosonic acid, and heptose. However, individual strains varied in the content of galactose, ribose, xylose, and arabinose. Three types of the O-PS structure were established, which differed in their configuration (alpha or beta), as well as in the type of the bond between glucosamine and rhamnose residues (1-->2 or 1-->3).

Endotoxin of Neisseria meningitidis composed only of intact lipid A: inactivation of the meningococcal 3-deoxy-D-manno-octulosonic acid transferase

Lipopolysaccharide, lipooligosaccharide (LOS), or endotoxin is important in bacterial survival and the pathogenesis of gram-negative bacteria. A necessary step in endotoxin biosynthesis is 3-deoxy-D-manno-octulosonic acid (Kdo) glycosylation of lipid A, catalyzed by the Kdo transferase KdtA (WaaA). In enteric gram-negative bacteria, this step is essential for survival. A nonpolar kdtA::aphA-3 mutation was created in Neisseria meningitidis via allelic exchange, and the mutant was viable. Detailed structural analysis demonstrated that the endotoxin of the kdtA::aphA-3 mutant was composed of fully acylated lipid A with variable phosphorylation but without Kdo glycosylation. In contrast to what happens in other gram-negative bacteria, tetra-acylated lipid IV(A) did not accumulate. The LOS structure of the kdtA::aphA-3 mutant was restored to the wild-type structure by complementation with kdtA from N. meningitidis or Escherichia coli. The expression of a fully acylated, unglycosylated lipid A indicates that lipid A biosynthesis in N. meningitidis can proceed without the addition of Kdo and that KdtA is not essential for survival of the meningococcus.

Structural analyses of the lipopolysaccharides from Chlamydophila psittaci strain 6BC and Chlamydophila pneumoniae strain Kajaani 6

Lipopolysaccharides (LPSs) of Chlamydophila psittaci 6BC and Chlamydophila pneumoniae Kajaani 6 contain 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo), GlcN, organic bound phosphate, and fatty acids in the molar ratios of approximately 3:2:2.2:4.8 and approximately 2.9:2:2.1:4.9, respectively. The LPSs were immunoreactive with a monoclonal antibody against a family-specific epitope of chlamydial LPS. This finding, together with methylation analyses of both LPSs and MALDI-TOF MS experiments on de-O-, and de-O,N-acylated LPSs, indicate the presence of a Kdo trisaccharide proximal to lipid A having a structure alpha-Kdo-(2-->8)-alpha-Kdo-(2-->4)-alpha-Kdo, which appears to be the main component of the core region in the native chlamydial LPSs. In the de-O-acylated LPSs from Chl. psittaci 6BC and Chl. pneumoniae Kajaani 6, two major molecular species are present that differ in distribution of amide-bound hydroxy fatty acids over both GlcN. It appears that either two (R)-3-hydroxy-18-methylicosanoic acids or one (R)-3-hydroxy-18-methylicosanoic acid and one (R)-3-hydroxyicosanoic acid are attached to the GlcN residues. In contrast, the de-O-acylated LPS of Chl. psittaci PK 5082 contains one major molecular species that has two (R)-3-hydroxyicosanoic acid residues attached to two GlcN residues.

Isolation and partial chemical analysis of firmly bound exopolysaccharide from adherent cells of a freshwater sediment bacterium

Cells of a freshwater sediment bacterium produced firmly bound extracellular polymers in laboratory cultures which, at the ultrastructural level, resembled those produced by natural sediment bacterial populations. Production of the exopolymers during subculture was maintained by using as a source of inoculum the population of cells which adhered to each other and to the wall of the glass culture vessel. The exopolymers were selectively released from the cells by blending and centrifugation in the presence of EDTA. Evaluation of glucose-6-phosphate dehydrogenase activity and 2-keto-3-deoxyoctonate concentration indicated that only small amounts of intracellular and cell wall components were released from the cells during exopolymer removal. Chemical analysis of the isolated crude exopolymer material indicated that it contained protein, polysaccharide, and DNA. The treatment promoted the selective isolation of firmly bound polymers from the surface of adherent cells.

Update on the detection of beta-exotoxin in Bacillus thuringiensis strains by HPLC analysis

AIMS

The current work aimed to study the presence of beta-exotoxin by high-performance liquid chromatography (HPLC) in supernatant fluids from final whole cultures of the 69 type strains and 13 subtypes of Bacillus thuringiensis strains, as well as from some insecticidal strains.

METHODS AND RESULTS

Results from HPLC and bioassays with Ephestia kuhniella (Lepidoptera Pyralidae) were compared. Type I beta-exotoxin was only detected in type strains representing serotypes H1, H9 and H10a,10b. Discrepancies between HPLC and bioassays were found in H8a,8b and some insecticidal strains, which suggests the occurrence of another soluble toxin different from type I beta-exotoxin, possibly type II beta-exotoxin.

CONCLUSION

This study shows the need to use bioassays to determine the presence of beta-exotoxin activity. However, HPLC is a fast and sensitive technique if only type I beta-exotoxin is to be determined. The occurrence of beta-exotoxin in a type strain does not imply production of this metabolite by other strains belonging to the same serovar.

SIGNIFICANCE AND IMPACT OF THE STUDY

These results complete the characterization of type strains belonging to the International Entomopathogenic Bacillus Collection (Institut Pasteur, Paris, France).

Chemical and serological properties of lipopolysaccharides from Vibrio parahaemolyticus O-untypeable strains isolated from patients

Chemical and serological studies have been carried out on the O-antigenic lipopolysaccharides (LPS) of six strains, U-6443, W-90144, X-3972, AD-7999, 90A-6611 and KX-V212, of Vibrio parahaemolyticus isolated from patients. The O-serotypes of these strains have not been identified because they were not agglutinated by any diagnostic antisera against known O-serotype strains. A compositional sugar analysis of their LPS revealed that out of the six O-untypeable (OUT) strains, U-6443, W-90144 and AD-7999 strains belonged to chemotype II (chemotype of O2), 90A-6611 and KX-V212 strains to chemotype III (chemotype of O3, O5, O11 and O13) and X-3972 strain to chemotype IV (chemotype of O4). A structural analysis of LPS isolated from KX-V212 revealed that the inner core region of the LPS consisted of only one mole of 2-keto-3-deoxy-D-manno-octonic acid, which carried a phosphate group at position C4 and the outer core at position C5. In passive hemolysis tests performed by using LPS as the antigen to sensitize sheep red blood cells (SRBC), and diagnostic antisera (O1 to O11) or anti-whole-cell rabbit antisera raised against O12, O13 and the six OUT strains, strong cross-reactivity was observed among LPS derived from the strains belonging to chemotype II (U-6443, W-90144, AD-7999 and O2). Strong cross-reactivity was also observed between X-3972 (chemotype IV) and O4 LPS. In contrast, LPS from two of the strains belonging to chemotype III (90A-6611 and KX-V212) did not react with any of the antisera raised against known O-serotypes. Cross-absorption tests showed that the O-antigens of U-6443, W-90144 and AD-7999 were identical to that of O2, and the O-antigen of X-3972 to that of O4. On the other hand, after the absorption of antisera raised against 90A-6611 and KX-V212 with O2 cells, the hemolytic activities against SRBC sensitized with homologous LPS were still retained at a high titer, whereas the hemolytic activities against SRBC sensitized with LPS from other O-serotype strains were completely eliminated. A cross-absorption test revealed that the O-antigens of these two strains were identical to each other. Thus, it was demonstrated that the O-serotype of OUT strains 90A-6611 and KX-V212 was not involved in the known O-serotypes; rather it represented a novel serotype which has not hitherto been reported.

Chlamydia psittaci lipopolysaccharide. A reinvestigation of its chemical composition and structure

A lipopolysaccharide (LPS) of Chlamydia psittaci PK 5082 strain associated with enzootic abortion in ewes was isolated from embryonated hen eggs-grown elementary bodies (EBs) by a phenol/water procedure. Compositional analyses revealed the presence of 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo), glucosamine (GlcN), phosphorus, and fatty acids in a molar ratio of 2.6:2.0:2.4:4.4. GlcN was the only amino sugar detected. Methylation analysis of the LPS confirmed the presence of a Kdo trisaccharide proximal to lipid A having the structure Kdo-(2-->8)-Kdo-(2-->4)-Kdo, which appears to be a highly conserved region in native chlamydial LPSs. The complex fatty acid composition revealed the presence of ten different straight or branched (iso and anteiso) nonhydroxy fatty acids and thirteen 3-hydroxy fatty acids. The major nonhydroxy fatty acid was icosanoic acid and the most prominent 3-hydroxy fatty acid was 3-hydroxyicosanoic acid followed by 3-hydroxy-18-methylicosanoic acid. The 3-hydroxy fatty acids represented more than two thirds of the total fatty acid content and most of them were bound in amide linkages. In contrast, most nonhydroxy fatty acids were ester-linked. It appears that LPSs from various chlamydial species differ in fatty acid composition and distribution.

Isolation and chemical analysis of a lipopolysaccharide from the outer membrane of the oral anaerobic spirochete Treponema pectinovorum

Isolation of a putative lipopolysaccharide from the surface of the oral treponeme, Treponema pectinovorum, revealed it to contain larger amounts of 3-deoxy-D-manno-octulosonic acid compared with other oral Treponema species. This molecule was isolated from the outer membrane of T. pectinovorum and had chemical characteristics of a putative lipopolysaccharide. The yield of lipopolysaccharide was between 0.6% and to 1.1% of the bacterial dry weight. The purified molecule was resistant to the action of proteinases and consisted of both sugars and lipids. 3-Deoxy-D-manno-octulosonic acid and hexoses accounted for 6.1-8.7% and 17.6-20.2%, respectively of the dry weight. Carbohydrate compositional analysis revealed the presence of glucose, galactose, 2-acetamido-2-deoxy-glucose, rhamnose and 6-deoxy-talose in the molar ratio of 1.00:0.96:0.19:0.88:0.98, respectively. No heptose was detected. The fatty acid analysis determined the presence of straight chain, C13:00, C14:00, C15:00 and C17:00 acids, as well as branched chain, C13:00, C14:00 and two species of C15:00, acids. Electrophoretic analysis indicated that the lipopolysaccharide was present as two major species.

Structural analysis of the lipopolysaccharide from Chlamydia trachomatis serotype L2

The lipopolysaccharide (LPS) of Chlamydia trachomatis L2 was isolated from tissue culture-grown elementary bodies using a modified phenol/water procedure followed by extraction with phenol/chloroform/light petroleum. From a total of 5 x 10(4) cm2 of infected monolayers, 22.3 mg of LPS were obtained. Compositional analysis indicated the presence of 3-deoxy-D-manno-oct-2-ulopyranosonic acid (Kdo), GlcN, phosphorus, and fatty acids in a molar ratio of 2.8:2:2.1:4.5. Matrix-assisted laser-desorption ionization mass spectrometry performed on the de-O-acylated LPS gave a major molecular ion peak at m/z 1781.1 corresponding to a molecule of 3 Kdo, 2 GlcN, 2 phosphates, and two 3-hydroxyeicosanoic acid residues. The structure of deacylated LPS obtained after successive treatment with hydrazine and potassium hydroxide was determined by 600 MHz NMR spectroscopy as Kdoalpha2-->8Kdoalpha2-->4Kdoalpha2-->6D-GlcpNbeta1 -->6D-GlcpNalpha 1,4'-bisphosphate. These data, together with those published recently on the acylation pattern of chlamydial lipid A (Qureshi, N., Kaltashov, I., Walker, K., Doroshenko, V., Cotter, R. J., Takayama, K, Sievert, T. R., Rice, P. A., Lin, J.-S. L., and Golenbock, D. T. (1997) J. Biol. Chem. 272, 10594-10600) allow us to present for the first time the complete structure of a major molecular species of a chlamydial LPS.

Mitogenic activity of the outer membrane of Treponema denticola

The outer membrane (OM) was isolated by detergent extraction from Treponema denticola ATCC 35405, ATCC 33521 and ATCC 35404, representing serovars a, b and c, respectively, as well as from two fresh isolates of T. denticola. Strict precautions were undertaken against the introduction of contaminant lipopolysaccharide when the OM was isolated. The OM was active in mitogenic stimulation of C3H/HeOuJ mouse spleen cultures, but to a somewhat lesser extent than purified lipopolysaccharide (LPS) from Escherichia coli 055:B5. Polymyxin B only partially inhibited the response. Unheated OM abrogated mitogenic activity of E. coli LPS, but heated preparations enhanced the mitogenic activity of E. coli LPS, suggesting the presence of a heat-labile cytolytic factor associated with T. denticola OM in addition to a putative lipopolysaccharide and/or heat-stable lipoprotein.

Unconventional antigen retrieval for carbohydrate and protein antigens

Aldehyde fixation of tissues often adversely affects the reactivity of cellular proteins with antibodies. A most commonly used retrieval technique in immunohistochemistry is high-temperature microwave heating of sections from formaldehyde-fixed and paraffin-embedded tissues. Here we report that pretreatment of paraffin and ultrathin cryosections with N-glycanase F to remove N-glycosidically linked oligosaccharides can result in a dramatic increase in specificity and intensity of immunogold labeling for sugar moieties present on O-glycosidically linked oligosaccharides. This is demonstrated in the immunolocalization of poly alpha2,8 KDN (KDN, 2-keto-3-deoxy-D-glycero-D-galacto-nononic acid) of megalin in rat kidney. The mechanism of this retrieval procedure is most probably based on the elimination of sterical hindrance by large N-glycosidically linked oligosaccharides. Furthermore, we demonstrate that exposure of ultrathin cryosections to acidic conditions (pH 5.5) at ambient temperature prior to immunogold labeling can result in an increased labeling intensity. This effect was observed for megalin immunoreactive sites in proximal tubular epithelia of rat kidney. It is proposed that the mechanism of this retrieval procedure is based on the depolymerization of methylen and polymethylen bridges introduced by formaldehyde in the acidic milieu.

Histopathological effects of Bacillus thuringiensis on the alimentary canal of the sheep louse, Bovicola ovis

Sequential observations were made of the ultrastructural effects of Bacillus thuringiensis (Bt) subsp. kurstaki strain WB3S16 on midgut epithelial cells of the sheep biting louse, Bovicola ovis, after the lice were fed, ad libitum, a powdered preparation of Bt spores, delta-endotoxin crystals, and lysed cellular components. Light microscope observations revealed cytopathological changes to the midgut epithelial cells 4 h postfeeding. Transmission electron micrographs showed that the microvilli of the midgut epithelial cells became disrupted 4-8 h postfeeding, after which the cells became vacuolated and swollen, and the cell organelles lost definition and disappeared. Paralysis and death of B. ovis occurred between 8 and 12 h postfeeding, coincident with midgut cells lysis and release of cellular contents into the midgut lumen. The histopathological effects reported here are similar to those reported in lepidopteran and coleopteran larvae affected by the delta-endotoxin crystal proteins. The constituent fractions of the Bt preparation were tested for toxicity to B. ovis using a feeding bioassay. Native delta-endotoxin crystals were not toxic to B. ovis and remained intact in the midgut of the insect. There was no evidence that the native Bt crystal was involved in the cytopathology and death of the lice. However, in vitro solubilized delta-endotoxin crystal proteins were significantly toxic to B. ovis. In addition, a louse active toxin was associated with the Bt membranes and culture supernatant.

Quantitative analysis of thuringiensin by high-performance liquid chromatography using adenosine monophosphate as an internal standard

An analytical method for thuringiensin using adenosine monophosphate (AMP) as an internal standard is established. AMP, with high stability and availability, is an appropriate internal standard for thuringiensin quantitative analysis using high-performance liquid chromatography and ultraviolet absorbance detection at 260 nm. A good correlation between the concentration of thuringiensin and the peak-area ratios of thuringiensin to AMP is demonstrated. From this general equation of linear regression line, the concentration of thuringiensin can be assessed in fermentation broth or semi-purified product.

[Isolation and chemical characterization of type R lipopolysaccharides of a hypovirulent strain of Yersinia pestis]

The lipopolysaccharides LPS I and LPS II, isolated from the hypovirulent EV40 strain of Yersinia pestis, are composed only of type R lipopolysaccharides. This type consists of two forms a and b, depending on their solubility pattern in a solvent mixture containing varying proportions of chloroform, methanol, hexane, and hydrochloric acid. LPS I consists of one subtype, RIb, while LPS II consists of two subtypes, RIIa and RIIb. Analysis by gel electrophoresis shows that the mass of these lipopolysaccharide forms are in the vicinity of 2000-3000 Da. The RIb and RIIb subtypes, which are found in the majority of lipopolysaccharide I and II fractions, are composed of ketoses and amines that are similar to those occurring in LPS I and LPS II. In contrast, the two subtypes RIIa and RIIb are different both in terms of the composition of lipid A and the extent of its substitution. Certain fractions of RIIa contain only lipid A and 3-deoxy-D-manno-octulosonic acid (KDO), while other fractions of RIIb possess a lipid A, which is not substituted by arabinose. The whole set of these R-type lipopolysaccharide forms are excellent models for the study of the role of the primary structure of the polysaccharide region, and for the effect of lipid A substitution on the biological activity of bacterial lipopolysaccharides.

Prevalence of beta-exotoxin, diarrhoeal toxin and specific delta-endotoxin in natural isolates of Bacillus thuringiensis

Of newly isolated colonies with the appearance of Bacillus thuringiensis, 47.5% were found to produce the parasporal crystals characteristic of this species. These positive isolates were screened using the polymerase chain reaction for their possession of a gene encoding a specific protoxin type, CryIB. Strains with and without this gene were screened for their ability to produce beta-exotoxin and Bacillus cereus-type enterotoxin. It was found that 35% of the isolates possessed the cryIB gene; of these 83% also produced enterotoxin and 58% produced beta-exotoxin. No statistical significance was found for linkage between any of these characteristics. The probability, therefore, of isolating a strain of B. thuringiensis which specifically possessed the cryIB gene but did not produce either of the other, undesired, toxins, from the soil sample used, was 1.2%.

Structural characterization of the K antigens from Rhizobium fredii USDA257: evidence for a common structural motif, with strain-specific variation, in the capsular polysaccharides of Rhizobium spp

Rhizobium fredii participates in a nitrogen-fixing symbiosis with soybeans, in a strain-cultivar-specific interaction, and past studies have shown that the cell surface and extracellular polysaccharides of rhizobia function in the infection process that leads to symbiosis. The structural analysis of the capsular polysaccharides (K antigens) from strain USDA257 was performed in this study. The K antigens were extracted from cultured cells with hot phenol-water and purified by size exclusion chromatography. We isolated two structurally distinct K antigens, both containing a high proportion of 3-deoxy-D-manno-2-octulosonic acid (Kdo). The polysaccharides were characterized by matrix-assisted laser desorption ionization-time-of-flight-mass spectrometry, nuclear magnetic resonance spectrometry, and gas chromatography-mass spectrometry analyses. The primary polysaccharide, which constituted about 60% of the K-antigen preparation, consisted of repeating units of mannose (Man) and Kdo, [-->)3-beta-D-Manp-(1-->5)-beta-D-Kdop-(2-->], and a second polysaccharide consisted of 2-O-MeMan and Kdo, [-->)3-beta-D-2-O-MeManp-(1-->5)-beta-D-Kdop-(2-->]. These structures are similar to yet distinct from those of other strains of R. fredii and R. meliloti, and this finding provides further evidence that the K antigens of rhizobia are strain-specific antigens which are produced within a conserved motif.

Structure of the capsular polysaccharide from Alteromonas nigrifaciens IAM 13010T containing 2-acetamido-2,6-dideoxy-L-talose and 3-deoxy-D-manno-octulosonic acid

A capsular polysaccharide was obtained from Alteromonas nigrifaciens IAM 13010T by saline extraction. On the basis of 1H and 13C NMR spectroscopy, including one-dimensional (1D) NOE spectroscopy, 2D rotating-frame NOE spectroscopy (ROESY), and 1H-detected heteronuclear 1H,13C multiple-quantum coherence (HMQC), it was concluded that the polysaccharide contained inter alia an acidic sugar, 3-deoxy-D-manno-octulosonic acid (Kdo), and a rare amino sugar, 2-acetamido-2,6-dideoxy-L-talose (L-6dTalNAc, N-acetylpneumosamine), and has a pentasaccharide repeating unit of the following structure: [equation: see text]

Determination of 2-keto-3-deoxyoctulosonic acid (KDO) with high-performance anion-exchange chromatography (HPAEC): survey of stability of KDO and optimal hydrolytic conditions

A new method for 2-keto-3-deoxy-octulosonic acid (KDO) determination using high-performance anion-exchange chromatography was developed. KDO is well separated from Neu5Ac, and the response was linear from 20 pmol to 5 nmol. The method was used to examine the stability of KDO under various hydrolytic, conditions and to survey optimal hydrolytic conditions for release of KDO.

Extraction and characterization of the smooth-type lipopolysaccharide from Fusobacterium nucleatum JCM 8532 and its biological activities

The lipopolysaccharide (LPS) of Fusobacterium nucleatum JCM 8532 was isolated by hot-phenol water extraction. Most of the LPS was extracted in the phenolic phase and shown to be the smooth-type, whereas the aqueous phase contained mainly rough-type LPS. The chemical composition of the LPS was similar to that reported in other studies, but D-quinovosamine, which may be a major component of O-antigenic polysaccharide, and 3-deoxy-D-manno-2-octulosonic acid (Kdoi) were detected for the first time by gas chromatography-mass spectrometry. The biological activities of smooth-type LPS, including limulus activity, lethal toxicity, pyrogenicity, and B lymphocyte mitogenicity, were comparable to those of entero-bacterial LPS. Smooth-type LPS inhibited the cell growth and DNA synthesis of adult and fetal human gingival fibroblasts in a dose-dependent manner, suggesting that LPS may play a role in the occurrence of human gingivitis.

Structural study on a lipopolysaccharide from Coxiella burnetii strain Nine Mile in avirulent phase II

A lipopolysaccharide isolated from Coxiella burnetti strain Nine Mile in avirulent phase II contains in the lipid A proximal region D-mannose, D-glycero-D-manno-heptose, and 3-deoxy-D- manno-oct-2-ulosonic acid (Kdo) in the molar ratio 2:2:3. The primary structure 1 of the heptasaccharide was determined by glycose analysis, methylation analysis, ESI-MS, and FABMS. [sequence: see text]

Expression of new KDN-gangliosides in rainbow trout testis during spermatogenesis and their structural identification

The developmental expression of 2-keto-3-deoxy-D-glycero-D-galacto-nononic acid-containing glycosphingolipids (KDN-gangliosides) in rainbow trout testis during spermatogenesis was studied using a monoclonal antibody, mAb.kdn3G, which recognizes the KDN alpha 2-->3Gal beta 1-->epitope. A major KDN-ganglioside found in mature sperm, (KDN)GM3, KDN alpha 2-->3Gal beta 1-->4Glc beta 1-->Cer (where Cer is ceramide), was expressed in testis throughout all stages of its maturation. On the contrary, four new KDN-gangliosides which were reactive with mAb.kdn3G were not detected in mature sperm, although they were identified in immature testis and expressed during spermatogenesis. The structures of these KDN-gangliosides were established by chemical, enzymatic and immunochemical methods as: (i) (KDN)GD1a, KDN alpha 2-->3Gal beta 1-->3GalNAc beta 1-->4(KDN alpha 2-->3)Gal beta 1-->4Glc beta 1-->Cer; (ii) (KDN, Neu5Ac)GD1a, KDN alpha 2-->3Gal beta 1-->3GalNAc beta 1-->4(Neu5Ac alpha 2-->3)Gal beta 1-->4Glc beta 1-->Cer and Neu5Ac alpha 2-->3Gal beta 1-->3GalNAc beta 1-->4(KDN alpha 2-->3)Gal beta 1-->4Glc beta 1-->Cer; (iii) (KDN) GD1 alpha, KDN alpha 2-->3Gal beta 1-->3(KDN alpha 2-->6)GalNAc beta 1-->4Gal beta 1-->4Glc beta 1-->Cer; and (iv) (KDN,Neu5Ac)GD1 alpha, KDN alpha 2-->3Gal beta 1-->3(Neu5Ac alpha 2-->6)GalNAc beta 1-->4Gal beta 1-->4Glc beta 1-->Cer. (KDN)GD1a and (KDN,Neu5Ac)GD1a first appeared at an early stage of spermatogenesis, but (KDN)GD1 alpha and (KDN,Neu5Ac)GD1 alpha were not expressed until 2 months prior to spermiation. While (KDN)GM3 was previously shown to contain only 4-sphingenine (d18:1) acylated with a C16:0 fatty acid, the new KDN-gangliosides discovered in this study were composed of 4-hydroxysphinganine (t18:0) or 4-sphingenine (d18:1), and were acylated with a C24:1 or C16:0 fatty acid. A possible function of these KDN-gangliosides is suggested.