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-hydroxytetradecanoic, 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 ( or ), as well as in the type of the bond between glucosamine and rhamnose residues (1 2 or 1 3).     

Treatment of House Dust Allergy

A controlled trial of the treatment of asthma by injections of a commercially produced extract of house dust is reported on 96 patients. The patients were allocated at random to two groups. One group received extract of house dust in a carbol saline solution, the other a carbol saline solution only. Some patients in both groups were advised on dust control in their houses.Results were available for comparison from 70 patients, 33 treated and 37 controls. Neither the treatment with house dust extract nor advice on dust control was found to give any advantage.     

Collective Migration in House Dust Mites

House dust mites (Dermatophagoides pteronyssinus) are widespread in the furniture and mattresses of homes throughout Eurasia. Because human occupation induces wide diurnal fluctuations in temperature and relative humidity, the most favourable locations for mites change constantly and they must migrate repeatedly. Here, we triggered and studied mites migration movements to a new area. Mites migrated from a starting arena to a second arena through a diamond‐shaped corridor offering a choice between two branches of equal length. In this article, we show that local air dryness and a distant water source were both necessary to trigger collective migration. Males and nymphs had a higher probability of migration than larvae and females. When migrating, although both branches initially appeared to be chosen equally, most mites eventually ended up choosing one particular branch. When about 50 or more mites had passed, there was an obvious choice of branch. We used a modelling approach to show that these data support the hypothesis that mites lay an attractive trail that is reinforced by followers. Consequently, the consistency of the collective choice is higher as the number of migrants grows. This article is the first to observe dust mite migration as a collective phenomenon.     

Role of Mites in Allergy to House Dust

One hundred and thirty-two patients known or suspected of allergy to house dust were skin-tested with pure extracts of four varieties of dust mites. The results show that both Dermatophagoides culinae and D. pteronyssinus probably played important parts in sensitizing susceptible people, as did Glycyphagus destructor and G. domesticus in some cases. In some patients these results enabled successful desensitization against the dust to be carried out, and for corticosteroid therapy to be stopped. Hence the use of mite extracts is considered to be an important advance in the diagnosis of allergy to house dust.     

Groups and Sources of Yeasts in House Dust

House dust contains bacteria, mycelial fungi, microarthropods, and yeasts. House dust samples collected in 25 apartments in Moscow and the Moscow region were found to contain yeasts belonging to the genera Candida, Cryptococcus, Debaryomyces, Rhodotorula, Sporobolomyces, and Trichosporon. The most frequently encountered microorganisms were typical epiphytic yeasts, such as Cryptococcus diffluens and Rhodotorula mucilaginosa, which are capable of long-term preservation in an inactive state. The direct source of epiphytic yeasts occurring in the house dust might be indoor plants, which were contaminated with these yeasts, albeit to a lesser degree than outdoor plants. Along with the typical epiphytic yeasts, the house dust contained the opportunistic yeast pathogens Candida catenulata, C. guillermondii, C. haemulonii, C. rugosa, and C. tropicalis, which are known as the causal agents of candidiases. We failed to reveal any correlation between the abundance of particular yeast species in the house dust, residential characteristics, and the atopic dermatitis of the inhabitants.     

Characterization of the Lipopolysaccharides and Capsules of Shewanella spp.

Electron microscopy, sodium dodecyl sulfate-polyacrylamide gel electrophoresis with silver staining and ¹H, ¹³C, and ³¹P-nuclear magnetic resonance (NMR) were used to detect and characterize the lipopolysaccharides (LPSs) of several Shewanella species. Many expressed only rough LPS; however, approximately one-half produced smooth LPS (and/or capsular polysaccharides). Some LPSs were affected by growth temperature with increased chain length observed below 25°C. Maximum LPS heterogeneity was found at 15 to 20°C. Thin sections of freeze-substituted cells revealed that Shewanella oneidensis, S. algae, S. frigidimarina, and Shewanella sp. strain MR-4 possessed either O-side chains or capsular fringes ranging from 20 to 130 nm in thickness depending on the species. NMR detected unusual sugars in S. putrefaciens CN32 and S. algae BrY^DL. It is possible that the ability of Shewanella to adhere to solid mineral phases (such as iron oxides) could be affected by the composition and length of surface polysaccharide polymers. These same polymers in S. algae may also contribute to this opportunistic pathogen's ability to promote infection.     

Comparative Characterization of the Lipopolysaccharides of Different Pseudomonas fluorescensBiovar I Strains

From the biomass of five Pseudomonas fluorescensbiovar I strains, including the P. fluorescenstype strain IMV 4125 (ATCC 13525), lipopolysaccharides (LPS) were isolated (by extraction with a phenol–water mixture followed by repeated ultracentrifugation), as well as individual structural components of the LPS macromolecule: lipid A, the core oligosaccharide, and O-specific polysaccharide (O-PS). 3-Hydroxydecanoic, 2-hydroxydodecanoic, 3-hydroxydodecanoic, dodecanoic, hexadecanoic, octadecanoic, hexadecenoic, and octadecenoic fatty acids were present in lipid A of the LPS of all the strains studied. Glucosamine, ethanolamine, and phosphoethanolamine were revealed in the lipid A hydrophilic part of all of the strains. Glucose, rhamnose, mannoze, glucosamine, galactosamine, KDO, a trace amount of heptoses, ethanolamine, phosphoethanolamine, alanine, and phosphorus were identified as the main core components. Interstrain differences in the core oligosaccharide composition were revealed. Structural analysis showed that the O-PS of the type strain, as distinct from that of other strains, is heterogeneous and contains two types of repetitive units, including (1) three L-rhamnose residues (L-Rha), one 3-acetamide-3,6-dideoxy-D-galactose residue (D-Fuc3NAc) as a branching substitute of the L-rhamnan chain and (2) three L-Rha residues and two branching D-Fuc3NAc residues. The type strain is also serologically distinct from other biovar I strains due to the LPS O-chain structure, which is similar to those of the strains of the species Pseudomonas syringae, including the type strain. The data of structural analysis agree well with the results of immunochemical studies of LPS.     

Characterization of Lipid A,A Component of Lipopolysaccharides from Selenomonas ruminantium

Lipid components of a glycolipid, formerly designated as spot A, from the cells of Selenomonas ruminantium were investigated. The basic structure of this material had been previously shown to be β-glucosaminyl-l,6-glucosamine. The major component of O- and N-acyl side chains was β-OH C_13:0 acid when the cells were grown with added valerate. Approximately 85 % of the total amide linked fatty acids was this compound. A considerable amount of C_13:2 acid was also present as a component of O-acyl fatty acids. When the cells were grown in a glucose medium containing caproate, the major fatty acid component of the spot A compound was β-OH myristic and β-OH C_13:0: acids. ¹⁴C-Valerate or ¹⁴C-caproate, supplemented to the glucose medium, was incorporated into O- and N-acyl linked fatty acid moieties of the spot A compound. It was also shown that the spot A compound was the lipid A component of lipopolysaccharides of this organism.     

Characterization of a Serine Protease Homologous to House Dust Mite Group 3 Allergens from the Scabies Mite Sarcoptes scabiei

The scabies mite, Sarcoptes scabiei var. hominis, infests human skin, causing allergic reactions and facilitating bacterial infection by Streptococcus sp., with serious consequences such as rheumatic fever and rheumatic heart disease. To identify a possible drug target or vaccine candidate protein, we searched for homologues of the group 3 allergen of house dust mites, which we subsequently identified in a cDNA library. The native protein, designated Sar s 3, was shown to be present in the mite gut and excreted in fecal pellets into mite burrows within the upper epidermis. The substrate specificity of proteolytically active recombinant rSar s 3 was elucidated by screening a bacteriophage library. A preference for substrates containing a RS(G/A) sequence at the P1-P2′ positions was revealed. A series of peptides synthesized as internally quenched fluorescent substrates validated the phage display data and high performance liquid chromatography/mass spectrometry analysis of the preferred cleaved substrate and confirmed the predicted cleavage site. Searches of the human proteome using sequence data from the phage display allowed the in silico prediction of putative physiological substrates. Among these were numerous epidermal proteins, with filaggrin being a particularly likely candidate substrate. We showed that recombinant rSar s 3 cleaves human filaggrin in vitro and obtained immunohistological evidence that the filaggrin protein is ingested by the mite. This is the first report elucidating the substrate specificity of Sar s 3 and its potential role in scabies mite biology.     

Host-Symbiont Interactions: III. Purification and Partial Characterization of Rhizobium Lipopolysaccharides

The lipopolysaccharides of three strains each of Rhizobium leguminosarum, R. phaseoli, and trifolii have been purified and partially characterized. The last step in the purification procedure is gel filtration column chromatography using Sepharose 4B with an elution buffer consisting of ethylenediaminetetraacetic acid and triethylamine. Each of the lipopolysaccharides reported in this paper elutes as a symmetrical peak in the partially included volume of this Sepharose 4B column. The ratio of 2-keto-3-deoxyoctonate acid (a sugar which is characteristic of lipopolysaccharides) to hexose is constant throughout the carbohydrate-containing peaks as they elute from the Sepharose 4B. The compositions and immunodominant structures of the purified lipopolysaccharides vary as much among strains of a single Rhizobium species as among the different species of Rhizobium. There is no obvious correlation between the nodulation group to which a Rhizobium belongs and the chemical composition or immunochemistry of the Rhizobium's lipopolysaccharide. There is extensive crosslysis by phage of strains of R. trifolii, R. phaseoli, and R. leguminosarum. This suggests that the receptors for these cross-lysing phage reside either in nonlipopolysaccharide structures or in common structures within the lipopolysaccharide which are not detected by compositional or immunochemical analysis.     

Asthma,Airway Symptoms and Rhinitis in Office Workers in Malaysia: Associations with House Dust Mite (HDM) Allergy,Cat Allergy and Levels of House Dust Mite Allergens in Office Dust

A prevalence study was conducted among office workers in Malaysia (N= 695). The aim of this study was to examine associations between asthma, airway symptoms, rhinitis and house dust mites (HDM) and cat allergy and HDM levels in office dust. Medical data was collected by a questionnaire. Skin prick tests were performed for HDM allergens (Dermatophagoides pteronyssinus, Dermatophagoides farinae) and cat allergen Felis domesticus. Indoor temperature and relative air humidity (RH) were measured in the offices and vacuumed dust samples were analyzed for HDM allergens. The prevalence of D. pteronyssinus, D. farinae and cat allergy were 50.3%, 49.0% and 25.5% respectively. Totally 9.6% had doctor-diagnosed asthma, 15.5% had current wheeze and 53.0% had current rhinitis. The Der p 1 (from D. pteronyssinus) and Der f 1 (from D. farinae) allergens levels in dust were 556 ng/g and 658 ng/g respectively. Statistical analysis was conducted by multilevel logistic regression, adjusting for age, gender, current smoking, HDM or cat allergy, home dampness and recent indoor painting at home. Office workers with HDM allergy had more wheeze (p= 0.035), any airway symptoms (p= 0.032), doctor-diagnosed asthma (p= 0.005), current asthma (p= 0.007), current rhinitis (p= 0.021) and rhinoconjuctivitis (p< 0.001). Cat allergy was associated with wheeze (p= 0.021), wheeze when not having a cold (p= 0.033), any airway symptoms (p= 0.034), doctor-diagnosed asthma (p= 0.010), current asthma (p= 0.020) and nasal allergy medication (p= 0.042). Der f 1 level in dust was associated with daytime breathlessness (p= 0.033) especially among those with HDM allergy. Der f 1 levels were correlated with indoor temperature (p< 0.001) and inversely correlated with RH (p< 0.001). In conclusion, HDM and cat allergies were common and independently associated with asthma, airway symptoms and rhinitis. Der f 1 allergen can be a risk factor for daytime breathlessness.     

Identification and Characterization of Arsenic and Metal Compounds in Contaminated Soil,Mine Tailings,and House Dust Using Synchrotron-Based Microanalysis

A comprehensive understanding of the risk associated with metal-rich soils and other materials includes identification of the solid phases hosting the metals. Synchrotron microanalysis provides a powerful diagnostic tool to characterize metal-bearing particles in mine tailings, soils, lake sediments, windblown dust, and household dust. A near simultaneous combination of X-ray fluorescence, diffraction, and absorption experiments using a microfocused beam can provide information on elemental concentrations, crystal structure, and oxidation state of individual particles. This approach can distinguish multiple metal-hosting minerals and industrial compounds in a single sample. Our objective is to provide examples of the application of this technique to a range of materials representing potential risk to human or ecosystem health. These examples include arsenic-contaminated materials and metal-rich household dust. We have identified grains of scorodite and other arsenate minerals in mine tailings and associated airborne dust, arsenic trioxide in organic soils near an ore roaster, metallurgical products dispersed to the environment, and various metal-rich particles in household dust. A comparison of chemical analysis of individual particles using electron microprobe analysis and synchrotron-based X-ray fluorescence analysis is provided.     

Alpha-Actinin Is a New Type of House Dust Mite Allergen

Main indoor allergens for humans are from house dust mites. There are more than 30 allergens in Dermatophagoides farinae but only fourteen allergens have been identified from this mite including Der f 1–3, 6, 7, 10, 11, 13–18, and 22. A native allergen protein (Der f 24, 90 kDa) was purified from D. farinae by gel filtration and anionic exchange liquid chromatography combined with IgE immunodetection. Its primary structure was determined by Edman degradation, mass spectrometry analysis and cDNA cloning. Enzyme-linked immunosorbent assay inhibition tests (ELISA-IT), immunoblots, basophil activation test (BAT) and skin prick test (SPT) were performed to evaluate the allergenicity. It was identified as an alpha (α)-actinin containing a CaM-like domain with EF-hand motifs. Der f 24 reacted to sera from 85.4% (35/41) of patients on western blot analysis. It reduced ∼20% sera IgE reactivity to D. farinae extracts on a competitive ELISA. Eighty percent (8/10) of patients with D. farinae allergy showed positive reactions to Der f 24 in skin prick test. The expression of CD63 on basophils from patients was up-regulated by Der f 24 by ∼5.4-fold. Alpha-actinin was identified as a new type of house dust mite allergen. To the best of our knowledge, this is the first report of α-actinin as an allergen.     

Cognitive Factors Mediate Placebo Responses in Patients with House Dust Mite Allergy

Background

Placebo effects have been reported in type I allergic reactions. However the neuropsychological mechanisms steering placebo responses in allergies are largely unknown. The study analyzed whether and to what extend a conditioned placebo response is affecting type I allergic reactions and whether this response can be reproduced at multiple occasions.

Methods

62 patients with house dust mite allergy were randomly allocated to either a conditioned (n = 25), sham-conditioned (n = 25) or natural history (n = 12) group. During the learning phase (acquisition), patients in the conditioned group received the H₁-receptor antagonist desloratadine (5mg) (unconditioned stimulus/US) together with a novel tasting gustatory stimulus (conditioned stimulus/CS). Patients in the sham-conditioned control group received the CS together with a placebo pill. After a wash out time of 9 days patients in the conditioned and sham-conditioned group received placebo pills together with the CS during evocation. Allergic responses documented by wheal size after skin prick test and symptom scores after nasal provocation were analyzed at baseline, after last desloratadine treatment and after the 1^st and 5^th CS re-exposure.

Results

Both conditioned and sham-conditioned patients showed significantly decreased wheal sizes after the 1^st CS-evocation and significantly decreased symptom scores after the 1^st as well as after the 5^th evocation compared to the natural history control group.

Conclusions

These results indicate that placebo responses in type I allergy are not primarily mediated by learning processes, but seemed to be induced by cognitive factors such as patients’ expectation, with these effects not restricted to a single evocation.     

Lipopolysaccharides of Rhizobium

Hot phenol-water extractions were carried out of cells from 12 strains of the fast-growing rhizobia Rhizobium leguminosarum, Rhizobium phaseoli, Rhizobium trifolii and Rhizobium meliloti. Purified lipopolysaccharide preparations contain neutral sugars, hexosamines, 2-keto-3-deoxyoctonate and uronic acids. Glucose, galactose, mannose, rhamnose and fucose are present in the majority of the LPS-preparations, but in varying proportions. Heptose was only found in some of them. O-methylated sugars are present in small amounts is most preparations, the kind of sugar being characteristic for lipopolysaccharides from different species. The lipid A part of lipopolysaccharides from all strains examined has identical patterns of fatty acids, namely -OH-C_14:0, -OH-C_15:0 (anteiso branched), -OH-C_16:0 and -OH-C_18:0. Comparison of the total compositions of Rhizobium lipopolysaccharides shows many differences among different species as among strains of a single species. Nearly identical lipopolysaccharide compositions also exist among certain strains, which constitute the same chemotype and which are also immunologically related. In view of a possible role of surface carbohydrates of Rhizobium in the root nodule symbiosis, the specificity of the binding of legume lectins with exo- and lipopolysaccharides of Rhizobium is discussed.Non-Standard Abbreviations LPS lipopolysaccharide(s) - EPS exopolysaccharides(s) - cetavlon cetyltrimethylammoniumbromide - KDO 2-keto-3-deoxyoctonate - ECL equivalent chain length Part II on Surface Carbohydrates of Rhizobium     

Hyposensitization with Dermatophagoides pteronyssinus Antigen: Trial in Asthma Induced by House Dust

A double-blind clinical trial of hyposensitization with aqueous extracts of Dermatophagoides pteronyssinus (the house-dust mite) and human skin scales showed a substantial improvement in symptoms in 11 asthmatics allergic to house dust treated with the D. pteronyssinus extract and a reduction in their need for other therapy. Five patients were well for a year but six relapsed. These results contrasted with the generally unfavourable course of the patients treated with the extract of human skin scales. Asthma due to house-dust allergy may be substantially improved by hyposensitization with D. pteronyssinus extract.     

Lipopolysaccharides of Shigella sonnei

Immunobiological properties of native lipopolysaccharides (LPS) from virulent and avirulent strains of Shigella sonnei bacteria (LPS-V and LPS-A, respectively) were studied. In avirulent bacteria, LPS-V induced immunosuppressive activity specific of the virulent strain. LPS of the avirulent strain, whereas LPS-A lacked this property. Native LPS-V with immunosuppressive activity were isolated from the virulent strain by and immune affinity method. Treatment of LPS-V with phenol or TCA abolished its activity and converted it into the LPS-A form. The data showed that LPS-A can be converted back to the LPS-V form by redox treatment. This approach seems to be promising for activating LPS extracted from cells with TCA or a water-phenol mixture.