High-level phenol bioproduction by engineered Pichia pastoris in glycerol fed-batch fermentation using an efficient pertraction system

This study aimed to establish a high-level phenol bioproduction system from glycerol through metabolic engineering of the yeast Pichia pastoris (Komagataella phaffii). Introducing tyrosine phenol-lyase to P. pastoris led to a production of 59 mg/L of phenol in flask culture. By employing a strain of P. pastoris that overproduces tyrosine-a precursor to phenol-we achieved a phenol production of 1052 mg/L in glycerol fed-batch fermentation. However, phenol concentrations exceeding 1000 mg/L inhibited P. pastoris growth. A phenol pertraction system utilizing a hollow fiber membrane contactor and tributyrin as the organic solvent was developed to reduce phenol concentration in the culture medium. Integrating this system with glycerol fed-batch fermentation resulted in a 214 % increase in phenol titer (3304 mg/L) compared to glycerol fed-batch fermentation alone. These approaches offer a significant framework for the microbial production of chemicals and materials that are highly toxic to microorganisms.

Construction of Corynebacterium glutamicum cells as containers encapsulating dsRNA overexpressed for agricultural pest control

Double-stranded RNA (dsRNA) inducing RNA interference (RNAi) is expected to be applicable to management of agricultural pests. In this study, we selected a ladybird beetle, Henosepilachna vigintioctopunctata, as a model target pest that devours vegetable leaves, and examined the effects of feeding the pest sterilized microbes highly accumulating a target dsRNA for RNAi induction. We constructed an efficient production system for diap1*-dsRNA, which suppresses expression of the essential gene diap1 (encoding death-associated inhibitor of apoptosis protein 1) in H. vigintioctopunctata, using an industrial strain of Corynebacterium glutamicum as the host microbe. The diap1*-dsRNA was overproduced in C. glutamicum by convergent transcription using a strong promoter derived from corynephage BFK20, and the amount of dsRNA accumulated in fermented cells reached about 75 mg per liter of culture. In addition, we developed a convenient method for stabilizing the dsRNA within the microbes by simply sterilizing the diap1*-dsRNA-expressing C. glutamicum cells with ethanol. When the sterilized microbes containing diap1*-dsRNA were fed to larvae of H. vigintioctopunctata, diap1 expression in the pest was suppressed, and the leaf-feeding activity of the larvae declined. These results suggest that this system is capable of producing stabilized dsRNA for RNAi at low cost, and it will open a way to practical application of dsRNA as an environmentally-friendly agricultural insecticide.

Overexpression system for recombinant RNA in Corynebacterium glutamicum using a strong promoter derived from corynephage BFK20

In recent years, it has been shown that recombinant RNA molecules have a great potential in mRNA therapy and as novel agricultural pesticides. We developed a fundamental system for efficient production of target RNA molecules in Corynebacterium glutamicum, composed of a strong promoter named F1 and a terminator derived from corynephage BFK20 in a high-copy number plasmid vector. As a target model RNA for overexpression, we designed and used an RNA molecule [designated U1A*-RNA, ∼160 nucleotides (nt) long] containing a stem/loop II (SL-II, hairpin-II) structure from U1 small nuclear RNA (snRNA), which binds to U1A protein, forming a U1 sn-ribonucleoprotein, which is essential in the pre-mRNA splicing process. C. glutamicum strains harboring the U1A*-RNA expression plasmid were cultured and the total RNA was analyzed. We observed prominent expression of RNA corresponding to the U1A*-RNA transcript along with lower expression of a 3'-region-truncated form of the transcript (∼110 nt) in an rnc (encoding RNase III)-deficient strain. We also found that the produced U1A*-RNA bound to the U1A RNA-binding domain protein, which was separately prepared with C. glutamicum. In a batch cultivation using a fermentor, the total accumulated amount of the target RNA reached about 300 mg/L by 24 h. Thus, our results indicated that our system can serve as an efficient platform for large-scale preparation of an RNA of interest.

Plasmid copy number mutation in repA gene encoding RepA replication initiator of cryptic plasmid pHM1519 in Corynebacterium glutamicum

Cryptic plasmid pHM1519 is a rolling-circular replication mode plasmid of the pCG1 plasmid family in coryneform bacteria. The derived shuttle vector pPK4 is maintained at about 40-50 copies per chromosome in Corynebacterium glutamicum 2256 (ATCC 13869). We found that a mutation (designated copA1) within the repA gene encoding essential initiator protein RepA of the pHM1519-replicon increased the copy number of the mutant plasmid to about 800 copies per chromosome. The mutation was a single G to A base transition, which changed Gly to Glu at position 429 of the amino acid sequence of RepA. In silico secondary structure prediction of RepA suggested that Gly429 is situated in a disordered region in a helix-turn-helix motif, which is a typical DNA-binding domain. This study shows the first example of a high copy number of a C. glutamicum cryptic plasmid caused by an altered replication initiator protein.

Identification of novel long chain N-acylhomoserine lactones of chain length C20 from the marine phototrophic bacterium Rhodovulum sulfidophilum

Gram-negative bacterial quorum sensing is mainly regulated by an extracellularly produced N-acylhomoserine lactone (AHL). AHL consists of a lactone ring and an acyl chain, which generally varies from C₄ to C₁₈ in length and affords species-specific variety. In this study, we developed an ultra-high performance liquid chromatography tandem mass spectrometry system and detected two kinds of long chain AHLs with chain length C₂₀ from the reverse-phase thin layer chromatography-fractionated cultured supernatant of the marine photosynthetic bacterium Rhodovulum sulfidophilum. By fragmentation search analysis to detect compounds with a homoserine lactone ring moiety for data dependent acquisition, a minor AHL, presumed to be 3-OH-C₁₈-homoserine lactone (HSL), was also found. Among the detected C₂₀-HSLs, 3-OH-C₂₀-HSL was structurally identified and 3-OH-C_20:1-HSL was strongly suggested. To our knowledge, this is the first report to show a novel AHL with the longest C₂₀ acyl side chain found to date.

ABBREVIATIONS

AGC: automatic gain control; AHL: N-acylhomoserine lactone; CD: cyclodextrin; CID: collision induced dissociation; DDA: data dependent acquisition; EPI: enhanced product ion; FISh: fragment ion search; HCD: high energy collisional dissociation; HSL: homoserine lactone; IT: injection time; LC: liquid chromatography; MS: mass spectrometry; PRM: parallel reaction monitoring; RP: reverse phase; SRM: selected reaction monitoring; TLC: thin layer chromatography; UHPLC: ultra high performance liquid chromatography.

Biotemplated Synthesis of TiO2-Coated Gold Nanowire for Perovskite Solar Cells

Fibrous nanomaterials have been widely employed toward the improvement of photovoltaic devices. Their light-trapping capabilities, owing to their unique structure, provide a direct pathway for carrier transport. This paper reports the improvement of perovskite solar cell (PSC) performance by a well-dispersed TiO₂-coated gold nanowire (GNW) in a TiO₂ cell layer. We used an artificially designed cage-shaped protein to synthesize a TiO₂-coated GNW in aqueous solution under atmospheric pressure. The artificially cage-shaped protein with gold-binding peptides and titanium-compound-biomineralizing peptides can bind GNWs and selectively deposit a thin TiO₂ layer on the gold surface. The TiO₂-coated GNW incorporated in the photoelectrodes of PSCs increased the external quantum efficiency within the range of 350-750 nm and decreased the internal resistance by 12%. The efficient collection of photogenerated electrons by the nanowires boosted the power conversion efficiency by 33% compared to a typical mesoporous-TiO₂-nanoparticle-only electrode.

Selection of a novel peptide aptamer with high affinity for TiO2-nanoparticle through a direct electroporation with TiO2-binding phage complexes

We have developed an easy and rapid screening method of peptide aptamers with high affinity for a target material TiO₂ using M13 phage-display and panning procedure. In a selection step, the phage-substrate complexes and Escherichia coli cells were directly applied by electric pulse for electroporation, without separating the objective phages from the TiO₂ nanoparticles. Using this simple and rapid method, we obtained a novel peptide aptamer (named ST-1 with the sequence AYPQKFNNNFMS) with highly strong binding activity for TiO₂. A cage-shaped protein fused with both ST-1 and an available carbon nanotube-affinity peptide was designed and produced in E. coli. The multi-functional supraprotein could efficiently mineralize a titanium-compound around the surface of single-wall carbon nanotubes (SWNTs), indicating that the ST-1 is valuable in the fabrication of nano-composite materials with titanium-compounds. The structural analysis of ST-1 variants indicated the importance of the N-terminal region (as a motif of AXPQKX₆S) of the aptamer in the TiO₂-binding activity.

Molecular-based allergy diagnosis of allergic bronchopulmonary aspergillosis in Aspergillus fumigatus-sensitized Japanese patients

BACKGROUND

Distinguishing between patients with allergic bronchopulmonary aspergillosis (ABPA) and Aspergillus fumigatus (Af)-sensitized asthmatic patients without ABPA is sometimes difficult owing to the IgE-cross-reactivity between Af and other fungal allergens.

OBJECTIVE

To establish the usefulness of molecular-based allergy diagnostics using allergen components from Af in distinguishing ABPA from Af-sensitized asthma without ABPA.

METHODS

Sera from Japanese patients with ABPA (n = 53) and Af-sensitized asthma without ABPA (n = 253) were studied. The levels of IgE and IgG antibodies to allergen components from Af and IgE antibodies to different fugal allergen extracts were measured by ImmunoCAP. Comorbid atopic dermatitis (AD) was taken into consideration in the sensitization profile analysis.

RESULTS

Patients with ABPA possessed significantly higher levels of IgE antibodies to Asp f 1, and Asp f 2 than asthmatic patients without ABPA. The areas under the receiver operating characteristic curves for the levels of IgE to Asp f 1 and Asp f 2 as diagnostic markers of ABPA were 0.75 and 0.78, respectively. The presence of IgE positivity to Asp f 1 and/or Asp f 2 resulted in increased sensitivity while losing little specificity. Comorbid AD was associated with higher levels of IgE to Asp f 6 (manganese superoxide dismutase from Af, a ubiquitous pan-allergen in fungi) and low but positive levels of IgE to other Af-components, which hampered the serological discrimination of ABPA.

CONCLUSIONS AND CLINICAL RELEVANCE

The levels of IgE to Asp f 1 and/or Asp f 2 can effectively differentiate ABPA from Af-sensitized asthma, suggesting that the amounts of IgE specific for these molecules are markers for genuine Af-sensitization in ABPA. However, comorbid AD must be taken into consideration in the interpretation of high IgE to Asp f 6. Establishing of IgE-sensitization profiles using panel of Af-allergen components provides valuable information for distinguishing genuine vs. cross-reactive sensitization in Af-sensitized patients.

Thermo-stable carbon nanotube-TiO₂ nanocompsite as electron highways in dye-sensitized solar cell produced by bio-nano-process

We produced a thermostable TiO2-(anatase)-coated multi-walled-carbon-nanotube (MWNT) nanocomposite for use in dye-sensitized solar cells (DSSCs) using biological supuramolecules as catalysts. We synthesized two different sizes of iron oxide nanoparticles (NPs) and arrayed the NPs on a silicon substrate utilizing two kinds of genetically modified cage-shaped proteins with silicon-binding peptide aptamers on their outer surfaces. Chemical vapor deposition (CVD) with the vapor-liquid-solid phase (VLS) method was applied to the substrate, and thermostable MWNTs with a diameter of 6 ± 1 nm were produced. Using a genetically modified cage-shaped protein with carbon-nanomaterials binding and Ti-mineralizing peptides as a catalyst, we were able to mineralize a titanium compound around the surface of the MWNT. The products were sintered, and thin TiO2-layer-coated MWNTs nanocomoposites were successfully produced. Addition of a 0.2 wt% TiO2-coated MWNT nanocomposite to a DSSC photoelectrode improved current density by 11% and decreased electric resistance by 20% compared to MWNT-free reference DSSCs. These results indicate that a nanoscale TiO2-layer-coated thermostable MWNT structure produced by our mutant proteins works as a superior electron transfer highway within TiO2 photoelectrodes.

Biological construction of single-walled carbon nanotube electron transfer pathways in dye-sensitized solar cells

We designed and mass-produced a versatile protein supramolecule that can be used to manufacture a highly efficient dye-sensitized solar cell (DSSC). Twelve single-walled carbon-nanotube (SWNT)-binding and titanium-mineralizing peptides were genetically integrated on a cage-shaped dodecamer protein (CDT1). A process involving simple mixing of highly conductive SWNTs with CDT1 followed by TiO2 biomineralization produces a high surface-area/weight TiO2 -(anatase)-coated intact SWNT nanocomposite under environmentally friendly conditions. A DSSC with a TiO2 photoelectrode containing 0.2 wt % of the SWNT-TiO2 nanocomposite shows a current density improvement by 80% and a doubling of the photoelectric conversion efficiency. The SWNT-TiO2 nanocomposite transfers photon-generated electrons from dye molecules adsorbed on the TiO2 to the anode electrode swiftly.

Characterization of theL-Lysine Biosynthetic Pathway in the Obligate MethylotrophMethylophilus methylotrophus

The L-lysine biosynthetic pathway of the gram-negative obligate methylotroph Methylophilus methylotrophus AS1 was examined through characterization of the enzymes aspartokinase (AK), aspartsemialdehyde dehydrogenase, dihydrodipicolinate synthase (DDPS), dihydrodipicolinate reductase, and diaminopimelate decarboxylase. The AK was inhibited by L-threonine and by a combination of L-threonine and L-lysine, but not by L-lysine alone, and the activity of DDPS was moderately reduced by L-lysine. In an L-lysine producing mutant (G49), isolated as an S-(2-aminoethyl)-L-cysteine (lysine analog) resistant strain, both AK and DDPS were partially resistant to feedback inhibition. The ask and dapA genes encoding AK and DDPS respectively were isolated from the parental strain, AS1, and its G49 derivative. Comparison of the sequences revealed a point mutation in each of these genes in G49. The mutation in the ask gene altered aspartic acid in a key region involved in the allosteric regulation common to AKs, while a novel mutation in the dapA gene altered tyrosine-106, which was assumed to be involved in the binding of L-lysine to DDPS.

Characterization of a Unique MutantlysEGene, Originating fromCorynebacterium glutamicum, Encoding a Product That InducesL-Lysine Production inMethylophilus methylotrophus

lysE24 is an allele of lysE encoding an L-lysine exporter of Corynebacterium glutamicum. The mutant gene is able to induce L-lysine production in Methylophilus methylotrophus. Although lysE24 has a mutation in the middle of lysE that results in chain termination, the entire lysE locus, including the region downstream of the short open reading frame, is necessary for L-lysine production. We propose that separate polypeptides are synthesized from the lysE24 locus due to reinitiation of translation utilizing an existing start codon beyond the site of the frameshift, and present evidence that translational coupling is required to form the functional lysE24 product. In addition, expression of lysE24 induces L-lysine production in another methylotroph, Methylobacillus glycogenes. These data suggest that the lysE24 product is a split protein and that this curious feature might be a structure necessary for its functioning in certain obligate gram-negative methylotrophs.

Induction of Th1 immune responses to Japanese cedar pollen allergen (Cry j 1) in mice immunized with Cry j 1 conjugated with CpG oligodeoxynucleotide

We determined whether a major Japanese cedar pollen allergen (Cry j 1) conjugated with CpG oligodeoxynucleotide would enhance allergen-specific Th1 responses in mice. Cry j 1 conjugated with CpG (Cry j 1-CpG) induced IL-12 in the spleen cells of naïve mice. Cry j 1-CpG immunization of BALB/c mice suppressed anti-Cry j 1 IgE response and enhanced anti-Cry j 1 IgG(2a) to subsequent Cry j 1 and alum adjuvant injection. CD4(+)T cells isolated from the spleens in mice immunized with Cry j 1-CpG produced higher IFN-γ levels than did CD4(+)T cells obtained from mice as negative controls. Our results suggested that Cry j 1-CpG immunization can induce Cry j 1-specific Th1 immune responses, thereby inhibiting IgE response to the pollen allergen.

Two routes for pollen entering indoors: ventilation and clothes

BACKGROUND

The route by which pollen enters dwellings has not been clarified.

OBJECTIVE

To evaluate the amount of pollen entering dwellings by ventilation and adhesion to textile products.

METHODS

The amount of pollen clinging to fabrics (clothes, laundry, and futon bedding) out of doors was measured by quantification of Japanese cedar pollen antigen Cry j 1. The effect of air ventilation on the amount of pollen indoors was also investigated using several neighboring unoccupied apartments with an identical layout while controlling the ventilation conditions.

RESULTS

The amount of pollen adhering to futons was especially high. More than half of the pollen on futons or laundry remained on the surface, even after being brushed off by hand or shaken off. Vacuuming laundry and futons after airing out would be an effective way to decrease the amount of indoor pollen. A large amount of pollen entered dwellings through air ducts when the windows were closed and the ventilation fans working. Since most pollen that entered by ventilation remained near the windows, cleaning carefully and frequently near windows could reduce the amount of pollen indoors.

CONCLUSIONS

To decrease the amount of pollen indoors, special attention must be paid to textile products and ventilation systems during the pollen season.

Isolation and characterization of native Cry j 3 from Japanese cedar (Cryptomeria japonica) pollen

BACKGROUND

Japanese cedar (Cryptomeria japonica) pollinosis is the most prevalent allergy in Japan. Recently, the Japanese cedar pollen allergen Cry j 3 was cloned as a homologue of Jun a 3, which is a major allergen from mountain cedar (Juniperus ashei) pollen. However, native Cry j 3 has not been isolated and there are no reports on its allergenic activity. The aims of this study were to isolate native Cry j 3 and assess its immunoglobulin E (IgE)-binding capacity in patients with Japanese cedar pollinosis.

METHODS

Native Cry j 3 was purified from Japanese cedar pollen by multidimensional chromatography. We assessed the IgE-binding capacity using sera from patients allergic to Japanese cedar pollen by immunoblot analysis and ELISA. Moreover, we assayed the capacity of Cry j 3 to induce histamine release from the patients' leukocytes. We cloned cDNA corresponding to purified Cry j 3 from a cDNA library of Japanese cedar pollen.

RESULTS

We isolated native Cry j 3 as a 27-kDa protein. The IgE-binding frequency of Cry j 3 from the sera of patients allergic to Japanese cedar pollen was estimated as 27% (27/100) by ELISA. Cry j 3 induced the release of histamine from leukocytes. We cloned the cDNA and named it Cry j 3.8. Cry j 3.8 cDNA encoded 225 amino acids and had significant homology with thaumatin-like proteins.

CONCLUSIONS

Cry j 3 is a causative allergen in Japanese cedar pollinosis and may play crucial roles in the cross-reactivity with oral allergy syndrome.

Innovative metabolic pathway design for efficient l-glutamate production by suppressing CO2 emission

In the pathway of L-glutamic acid (L-Glu) biosynthesis in Corynebacterium glutamicum, 1 mol of L-Glu is synthesized from 1 mol of glucose at a cost of 1 mol of carbon dioxide (CO(2)), with a maximum theoretical yield of 81.7% by weight. We have designed an innovative pathway for efficient L-Glu production employing phosphoketolase (PKT) to bypass the CO(2)-releasing pyruvate dehydrogenase reaction, thereby increasing the maximum theoretical yield of L-Glu from glucose to up to 98.0% by weight (120% mol/mol L-Glu produced/glucose consumed). The xfp gene encoding PKT was cloned from Bifidobacterium animalis and overexpressed under the strong cspB promoter in C. glutamicum. A functional enzyme was detected in an L-Glu-producing strain of C. glutamicum (odhA). When cells of this producer strain with the xfp gene and those without the xfp gene were cultivated in a controlled fermentation system, the L-Glu production yield of the strain expressing the xfp gene was much higher than that of the original strain, coupled with the suppression of CO(2) emission. Consequently, we could successfully enhance L-glutamate production by installing the PKT pathway of B. animalis into C. glutamicuml-Glu metabolism, and this novel metabolic design will be able to increase L-Glu production yield beyond the maximum theoretical yield obtained from the conventional metabolic pathway of biosynthesis from glucose.

Enhancement of l-lysine production in methylotroph Methylophilus methylotrophus by introducing a mutant LysE exporter

The obligate methylotroph Methylophilus methylotrophus AS1 expressing a mutant form of dapA (dapA24) encoding a dihydrodipicolinate synthase desensitized from feedback inhibition by L-lysine could secrete L-lysine into the medium, but also maintained a high concentration of intracellular L-lysine. To improve the yield from excretion, we attempted to introduce an L-lysine/L-arginine exporter (LysE) from Corynebacterium glutamicum 2256 into M. methylotrophus. We were unable to stably transform M. methylotrophus with a plasmid expressing the wild type lysE gene, but happened to obtain a transformant carrying a spontaneously mutated lysE gene (designated lysE24) which could induce L-lysine production even in the wild type strain. The transformant also possessed increased tolerance to S-(2-aminoethyl)-L-cysteine (an L-lysine analog). lysE24 has a single-base insertion mutation in the middle of the lysE gene, and its product is presumably quite different in structure from wild-type LysE. When lysE24 was introduced into an L-lysine producer of M. methylotrophus carrying dapA24, the level of intracellular L-lysine fell. During fermentation, M. methylotrophus carrying both lysE24 and dapA24 produced 10-fold more L-lysine (11.3 gl(-1) in jar-fermentation) than the parent producer carrying only dapA24 or lysE24. These results show the importance of the factor (lysE24) involved in the excretion of L-lysine on its overproduction in M. methylotrophus.

l-Lysine biosynthetic pathway of Methylophilus methylotrophus and construction of an l-lysine producer

Previously, we showed that the enzymes aspartokinase (AK) and dihydrodipicolinate synthase (DDPS), which are involved in L-lysine biosynthesis in the Gram-negative obligate methylotroph Methylophilus methylotrophus AS1, were inhibited by allosteric effectors, including L-lysine. To elucidate further the regulation of L-lysine biosynthesis in M. methylotrophus, we cloned the genes encoding three other enzymes involved in this pathway, L-aspartate-beta-semialdehyde dehydrogenase, dihydrodipicolinate reductase (DDPR) and diaminopimelate decarboxylase, and examined their properties. DDPR was markedly inhibited by L-lysine. Based on this and our previous results, we constructed an L-lysine-producing strain of M. methylotrophus by introducing well-characterized genes encoding desensitized forms of AK and DDPS, as well as dapB (encoding DDPR) from Escherichia coli, using a broad host range plasmid. L-Lysine production was significantly increased by employing an S-(2-aminoethyl)-L-cysteine (L-lysine analog)-resistant mutant as the host. This derivative accumulated L-lysine at a concentration of 1 g l(-1) of medium using methanol as a carbon source.

HxlR, a member of the DUF24 protein family, is a DNA-binding protein that acts as a positive regulator of the formaldehyde-inducible hxlAB operon in Bacillus subtilis

The HxlR protein from Bacillus subtilis belongs to the DUF24 protein family (InterPro No. IPR002577) of unknown function. The hxlR gene that encodes this protein is located upstream of the hxlAB operon. This operon encodes two key enzymes in the ribulose monophosphate pathway that are involved in formaldehyde fixation, 3-hexulose-6-phosphate synthase and 6-phospho-3-hexuloisomerase. Expression of the hxlAB operon is induced by the presence of formaldehyde. Recombinant HxlR prepared from Escherichia coli showed specific binding to a region of DNA upstream of the hxlAB operon. Using gel-retardation and DNase I footprinting assays, we identified two 25 bp binding regions for HxlR within the upstream DNA. Surface plasmon resonance analyses suggested that two HxlR dimers sequentially bound to the DNA. Finally, we demonstrated that each of the two binding regions for HxlR was necessary for formaldehyde-induced expression of the hxlAB operon in B. subtilis. Thus, we have shown that HxlR is a DNA-binding protein that is necessary for formaldehyde-induced expression of hxlAB in B. subtilis.

Improved production of L-lysine by disruption of stationary phase-specific rmf gene in Escherichia coli

Growth and rate, at which fermentation products are formed in cells, generally decreases during the stationary phase as a result of changes in gene expression. We focused on the rmf gene, which encodes the ribosome modulation factor protein, as a target for strain modification in order to improve the rate of L-lysine production in Escherichia coli. Increased expression of the rmf gene during the stationary phase was confirmed under various cultivation conditions using DNA macroarray analysis. Mutants with disrupted rmf were then generated from an L-lysine-producing E. coli strain. The rates of L-lysine accumulation and production were significantly increased in disruptants that were cultivated with excess phosphate. By contrast, a higher biomass was generated in disruptants that were grown under limited phosphate conditions. These results demonstrate that disruption of the rmf gene significantly affects L-lysine production and growth in E. coli.

Identification of peptides containing T-cell epitopes of Japanese cedar (Cryptomeria japonica) pollen allergen (Cry j 1) in dogs

Japanese cedar (Cryptomeria japonica, CJ) pollen has been known to cause atopic dermatitis in dogs in Japan. However, since the mechanism of the CJ antigen recognition is not well understood in dogs, it is difficult to develop effective immunotherapy for atopic dermatitis caused by sensitization to CJ pollen. In order to aim at development of a peptide immunotherapy, we tried to identify T-cell epitopes of a major allergen of CJ pollen, Cry j 1, in dogs sensitive to CJ pollen allergen. Peripheral blood mononuclear cells (PBMCs) obtained from 22 dogs experimentally sensitized to CJ pollen allergen and 5 atopic dogs sensitive to CJ pollen allergen were used for mapping of T-cell epitopes of Cry j 1 using 35 kinds of synthesized overlapping peptides of Cry j 1. Reactive peptides were identified based on the results of blastogenic responses of PBMCs against the peptides when the stimulation indices were beyond 2.0. Three reactive peptides were identical in a relatively high population of experimental dogs, which were Nos. 8 (p71-90) (41%), 10 (p91-110) (50%), and 11 (p101-120) (41%). It was considered that these synthesized peptides should contain T-cell epitopes of Cry j 1 in the dogs. However, there were no reactive peptides identical among the five atopic dogs spontaneously sensitive to CJ pollen. The population of dogs experimentally sensitized to CJ pollen antigen will be used in order to investigate effects of a peptide immunotherapy using the reactive peptides. The results in atopic dogs sensitive to CJ pollen antigen will also provide useful information on necessity to develop a tailor-made immunotherapy using reactive peptides in each dog.

Effects of lysed Enterococcus faecalis FK-23 on allergen-induced serum antibody responses and active cutaneous anaphylaxis in mice

BACKGROUND

Our previous studies have presented evidence that lysed Enterococcus faecalis FK-23 (LFK), a lysozyme and heat-treated probiotic product, can inhibit allergen-induced local accumulation of eosinophils in mice.

OBJECTIVE

The purpose of this experimental study was to evaluate the influence of orally administrated LFK on the host immune responses.

METHODS

BALB/c mice were sensitized subcutaneously, and challenged intraperitoneally by cedar pollen allergen. Blood and spleen samples were collected after oral administration of LFK 60 mg/day for 21 days. The serum levels of total and allergen-specific IgE and IgG2a antibodies and the production of IL-4, IL-5 and IFN-gamma generated by allergen-stimulated cultured splenocytes were determined. Additionally, the effect of LFK on active cutaneous anaphylaxis (ACA) induced by ovalbumin (OVA) challenge in mice was measured after 28 days LFK treatment.

RESULTS

No significant differences in serum immunoglobulin levels, as well as in cytokine production of splenocytes were observed between LFK-treated and control mice (P>0.05). There was, however, an increasing tendency of allergen-specific IgG2a level in mice after LFK treatment for 21 days compared with controls (P=0.060). Furthermore, the serum ratio of specific IgE to IgG2a was found to be significantly decreased in the LFK group (P=0.005). In addition, a significant inhibition of OVA-induced ACA reaction was observed in mice that had been fed for 28 days with LFK compared with control mice (P=0.008).

CONCLUSION

These results suggest that LFK shows an anti-inflammatory effect, which may be part of the mechanism for protection against IgE-mediated allergy.

Cry j 1 isoforms derived from Cryptomeria japonica trees have different binding properties to monoclonal antibodies

BACKGROUND

We identified five Cryptomeria japonica trees producing Cry j 1 isoforms that cannot be detected in a sandwich ELISA using two monoclonal antibodies, J1B01 and J1B07, suggesting that the binding affinity of these isoforms for both monoclonal antibodies is low.

OBJECTIVES

The binding properties of the Cry j 1 isoforms produced by five trees to J1B07 and J1B01 were examined. The complementary DNA (cDNA) sequences of the Cry j 1 isoforms were also determined.

METHODS

To clarify the binding properties of these Cry j 1 isoforms to J1B01 and J1B07, Cry j 1 was quantified in pollen samples collected from each of the five trees, by sandwich ELISAs using polyclonal antibodies and either J1B01 or J1B07. The cDNA sequences of isoforms with different binding properties were determined. To test the assumption that amino acid substitutions affect the binding affinities of Cry j 1 isoforms for monoclonal antibodies, cleaved amplified polymorphic sequences (CAPS) markers representing the putative polymorphisms were used to analyse additional trees.

RESULTS

Four of the five trees produced Cry j 1 isoforms with extremely low binding affinity for J1B07, whereas the other tree produced two different isoforms with low binding affinity for either J1B01 or J1B07. Cry j 1-encoding cDNA sequences for one of the four trees and for the exceptional fifth tree indicate that amino acid substitutions at positions 55 and 352 in mature Cry j 1 affect its binding to J1B01 and J1B07, respectively. This was supported by the results of CAPS analysis.

CONCLUSION

The existence of Cry j 1 isoforms with low binding affinity for either J1B01 or J1B07 was established. Furthermore, a single amino acid substitution is involved in this difference in binding affinity for each monoclonal antibody.

Th1-dominant shift of T cell cytokine production, and subsequent reduction of serum immunoglobulin E response by administration in vivo of plasmid expressing Txk/Rlk, a member of Tec family tyrosine kinases, in a mouse model

BACKGROUND

Th1 and Th2 cells, resulting from antigenic stimulation in the presence of IL-12 and IL-4, respectively, are implicated in the pathology of various diseases including allergic and autoimmune diseases. Txk/Rlk is a member of Tec family tyrosine kinases. We reported that Txk acts as a Th1-specific transcription factor in the T lymphocytes.

OBJECTIVE

In this study we have asked whether administration of txk expression plasmid brings about a Th1/Th2 shift in vivo of the mice, and subsequent reduction of circulating IgE.

METHODS

Mice were administered a txk expression plasmid with hemagglutinating virus of Japan (HVJ) envelope vector. Txk expressions in spleen cells were assessed by immunoblotting and immunocytochemical staining. Cytokine productions by the spleen cells and serum Ig concentrations were studied by ELISA.

RESULTS

Administration of a txk expression plasmid with HVJ vector induced expression of Txk in the spleen cells. The spleen cells showed enhanced Th1-specific cytokine production; spleen cells from the txk administered mice produced more IFN-gamma as compared with those from control plasmid-administered mice in an antigen-specific manner. IL-2 and IL-4 secretions of the spleen cells were comparable between the two mouse groups. Txk administration did not reduce serum IgG concentration. It markedly reduced total IgE level and an IgG1/IgG2a ratio, reflection of Th1/Th2 balance, in sera. Furthermore, txk administration reduced ovalbumin (OVA)-specific IgE levels in sera of the OVA sensitized mice.

CONCLUSION

Thus, Txk enhances IFN-gamma secretion and thus modulates Th1/Th2 cytokine balance, leading to reduction of serum IgE.

Measurement of Dermatophagoides mite allergens on bedding and human skin surfaces

BACKGROUND

The level of the Dermatophagoides mite group 1 (Der 1) allergens in reservoir dust has been used as an index of exposure in most studies. However, the mite allergen level in reservoir dust cannot directly reflect the personal exposure level.

OBJECTIVE

We sought to develop a new method for quantifying the Der 1 allergens on bedding and human skin surfaces as an index of exposure to mite allergens.

METHODS

Samples were obtained with a small adhesive tape from the forearm skin of 30 healthy volunteers and from their regularly used mattresses. The level of Der 1 allergens collected onto the adhesive tape was measured by a newly developed sensitive fluorometric ELISA for Der p 1 and Der f 1.

RESULTS

The Der 1 allergens could be detected in all the samples from bedding surfaces and in 28 of the 30 samples from skin surfaces. The Der 1 levels by adhesive tape sampling from the mattresses correlated with those by reservoir dust sampling. The sampling of the skin and bedding surface with adhesive tape correlated, but skin sampling did not correlate with reservoir sampling.

CONCLUSION

The Der 1 allergens on bedding surfaces and on human skin surfaces could be quantified with a very simple sampling technique. The system developed in this study will provide a new tool for the assessment of mite allergen exposure in daily life.

The ribulose monophosphate pathway operon encoding formaldehyde fixation in a thermotolerant methylotroph, Bacillus brevis S1

The hps and phi genes encoding 3-hexulose-6-phosphate synthase and 6-phospho-3-hexuloisomerase, the key enzymes of the ribulose monophosphate (RuMP) pathway for formaldehyde fixation, were cloned from the chromosomal DNA of a thermotolerant methylotroph, Bacillus brevis S1. Enzyme induction and Northern blot analyses revealed that both the hps and phi genes are induced by methanol or ethanol, and that their expression is controlled polycistronically at the transcription stage. Sequence analysis also suggested that the hps and phi genes constitute an RuMP operon. The gene organization of the RuMP operon and its surrounding region are unique among bacteria possessing the RuMP pathway genes.

The effect of house design and environment on fungal movement in homes of bronchial asthma patients

The effect of house building design and environment on the fungal movement in the houses of 41 bronchial asthma (BA) patients has been investigated by examining house dust. The presence and composition of fungi were determined and compared in relation to building structure, house age, size of living room, main flooring material, presence of a living-room rug or air purifier, and frequency of vacuum cleaning. Among these elements, fungal CFU apparently varied only between building structure: wooden-board houses had significantly higher numbers of fungi than reinforced concrete houses (p < 0.01), and wooden mortar or iron-framed prefabricated houses had significantly higher numbers of fungi than reinforced concrete houses (p < 0.05). Classification of the types of fungi present in the house dust of BA patients showed that, regardless of the building designs, there were high levels of osmophilic fungi (group A) and fungi that survive at relatively dry conditions (group B), whereas fungi that survive in very wet conditions (group D) were present at low frequency.

IgE reactivity and cross-reactivity to Japanese cedar (Cryptomeria japonica) and cypress (Chamaecyparis obtusa) pollen allergens in dogs with atopic dermatitis

The natural occurrence of Japanese cedar (Cryptomeria japonica) pollinosis has been reported in dogs with atopic dermatitis. However, the reactivity to Japanese cypress (Chamaecyparis obtusa) pollen allergens in these dogs has not been reported. The present study was designed to investigate the reactivity to Japanese cypress pollen allergens in dogs sensitized to Japanese cedar pollen allergens. In 19 dogs with specific IgE to C. japonica pollen allergen, we measured the specific IgE to C. obtusa pollen allergen and examined the reactivity to the allergen by intradermal test. Of the 19 dogs, 18 had specific IgE to crude and purified major allergens (Cha o 1) of C. obtusa pollen. Most of the dogs showed a positive reaction to C. obtusa pollen allergens in the intradermal test. Allergenic cross-reactivity between Cha o 1 and Cry j 1 (a major allergen in C. japonica pollen) was observed by the ELISA inhibition method. Dogs sensitized to Japanese cedar pollen allergens demonstrate reactivity to Japanese cypress pollen allergens.

Analysis of the canine IgE-binding epitope on the major allergen (Cry j 1) of Japanese cedar pollen with anti-Cry j 1 monoclonal antibodies

In our previous study [Immunology 91 (1997) 161] using monoclonal antibodies (mAbs) specific to Cry j 1, a major allergen in Japanese cedar (Cryptomeria japonica) pollen, we identified five independent epitopes (EP-1-EP-5) on the molecule and found that EP-1 and EP-5 are the predominant allergic epitopes for humans and monkeys, respectively. In this study, we analyzed the epitopes recognized by IgE in the sera of 10 dogs sensitive to C. japonica pollen allergen using an IgE-ELISA inhibition method with these mAbs. The IgE reaction patterns varied among dogs. In eight of the 10 dogs, IgE recognized EP-5 which is a predominant allergic epitope for monkeys with the pollenosis. In four dogs, IgE recognized EP-1 which is a predominant allergic epitope for human patients with the pollenosis. In three dogs, IgE recognized EP-4 which is a heat-stable epitope. EP-5 is a predominant allergic epitope for dogs and some, but not all, dogs have IgE reaction patterns to the epitopes similar to those of humans.

Affinity of IgE antibody to antigen influences allergen-induced histamine release

BACKGROUND

Although affinity of an antibody for an antigen is recognized to be an important factor in determining its biological effects, little is known about the relevance of such affinity of IgE antibodies to the functional response.

OBJECTIVES

To investigate the effect of IgE antibody affinity to Der p 2 on Der p 2-induced histamine release from human basophils.

METHODS

The most probable value of the dissociation constant (Kd) of IgE antibody to Der p 2 was calculated and histamine release by Der p 2-challenged leucocytes was used to evaluate the biological efficacy of the IgE antibody.

RESULTS

The most probable Kd value of IgE antibody to Der p 2 ranged from 5.6 to 177.8 pM in 14 asthmatic patients sensitive to Der p 2. A significant correlation was observed in Der p 2-induced histamine release between the sensitivity and the Kd value for Der p 2-specific IgE antibody (rs = 0.797, P = 0.0040), suggesting that the higher the affinity, the lower the amount of allergen required for the release of a specific level of histamine.

CONCLUSION

Apart from the changes associated with the reactivity, the sensitivity of histamine release is closely related to the affinity of IgE antibody for its antigen.

[Change in skin reactivity to common allergens in allergic patients over a 30-year period. Association with aeroallergen load]

Five-year changes in the percentage of positive intradermal test to allergens in patients with bronchial asthma (BA) and allergic rhinitis (AR) over a period of 30 years from 1969 to 1998 were analyzed, with consideration of their association with the yearly changes in the levels of airborne pollens and molds over 30 years. Allergens used throughout the period were house dust, pollens from various plants (Japanese cedar, pine, oak, Japanese alder, Zelkova, orchard grass, ragweed, mugwort and Japanese hop) and molds (Alternaria, Cladosporium, Aspergillus, Penicillium and Candida). Overall percentages to house dust were higher in BA patients than in AR patients, but those to pollens were distinctly higher in the latter. Those to molds were higher in BA patients, except that those to Alternaria were about the same in both BA and AR patients. Therefore, the clinical expression of allergy may differ according to the type of allergen to which subjects are sensitized. Over the course of 30 years, the increase in the percentage of positive intradermal test to all of the allergens used was noted in both BA and AR patients, although this did not always reflect the aeroallergen load. This includes the two extremes to pollens from Japanese cedar and pine, either of which is the most common source of allergen in Japan. Significant increases in the percentages to Japanese cedar pollen (from 12.5% to 54.4% in BA patients, and from 35.1% to 81.5% in AR patients) appeared to be roughly correlated to marked increases in pollen count. In contrast, that to pine pollen was kept low at about 2%, because of their weak allergenicity, but abruptly increased to 5-6% in the last decade, despite the almost invariable pollen count over the last 30 years. Therefore, the increased sensitivity to aeroallergens may also be associated with other factors besides their load in the air.

IgE-reactivity to major Japanese cedar (Cryptomeria japonica) pollen allergens (Cry j 1 and Cry j 2) by ELISA in dogs with atopic dermatitis

The present study investigated IgE-reactivity to two major Japanese cedar (Cryptomeria japonica, C. japonica) pollen allergens (Cry j 1 and Cry j 2) in dogs with atopic dermatitis by use of a fluorometric ELISA. The serum samples from 27 dogs that showed IgE-sensitivity to crude C. japonica pollen allergen by ELISA were tested for specific IgE to the two major allergens. All 27 dogs had anti-Cry j 1 IgE, and 10 (37%) had anti-Cry j 2 IgE. Inhibition of binding of dog specific IgE to crude C. japonica pollen allergen was carried out by addition of Cry j 1. When serum samples containing anti-Cry j 1 IgE but no anti-Cry j 2 IgE were incubated with Cry j 1, specific IgE binding to crude C. japonica pollen allergen was almost abolished. These findings suggest that Cry j 1 is a major allergen in dogs.

Identification and characterization of a group 2 conifer pollen allergen from Chamaecyparis obtusa, a homologue of Cry j 2 from Cryptomeria japonica

BACKGROUND

Not only Cryptomeria japonica (Japanese cedar) pollen but also that of Chamaecyparis obtusa (Japanese cypress) induces the allergic symptoms of Japanese cedar pollinosis. However, allergens from C. obtusa pollen have not been as well characterized as those from C. japonica pollen.

OBJECTIVE

We sought to identify and characterize a homologue of the second major allergen of C. japonica pollen, Cry j 2, from the pollen of C. obtusa.

METHODS

An allergen homologous to Cry j 2 was identified in C. obtusa pollen extract by immunoblot analysis, probed with anti-Cry j 2 monoclonal antibodies and purified by a series of column chromatographic steps.

RESULTS

The allergen isolated from the extract showed a slightly diffuse band of 45 kDa and closely spaced double-bands of 42 and 45 kDa on SDS-PAGE, under reducing and non-reducing conditions, respectively; the bands were approximately 5-7 kDa larger than those of Cry j 2. In 24 of 30 residues, the N-terminal amino acid sequence of the allergen was identical with corresponding sequence in Cry j 2. Most patients with pollinosis who were IgE antibody-positive to Cry j 2 were shown to be IgE antibody-positive to this allergen, and the IgE antibody levels to both allergens were highly correlated.

CONCLUSION

The results indicate that the allergen isolated from C. obtusa pollen in this study is a homologue of Cry j 2. The allergen was designated as Cha o 2 according to the WHO/IUIS Allergen Nomenclature Subcommittee recommendation.

A novel operon encoding formaldehyde fixation: the ribulose monophosphate pathway in the gram-positive facultative methylotrophic bacterium Mycobacterium gastri MB19

A 4.2-kb PstI fragment harboring the gene cluster of the ribulose monophosphate (RuMP) pathway for formaldehyde fixation was identified in the chromosome of a gram-positive, facultative methylotroph, Mycobacterium gastri MB19, by using the coding region of 3-hexulose-6-phosphate synthase (HPS) as the hybridization probe. The PstI fragment contained three complete open reading frames (ORFs) which encoded from the 5' end, a DNA-binding regulatory protein (rmpR), 6-phospho-3-hexuloisomerase (PHI; rmpB), and HPS (rmpA). Sequence analysis suggested that rmpA and rmpB constitute an operon, and Northern blot analysis of RNA extracted from bacteria grown under various conditions suggested that the expression of the two genes is similarly regulated at the transcriptional level. A similarity search revealed that the proteins encoded by rmpA and rmpB in M. gastri MB19 show high similarity to the unidentified proteins of nonmethylotrophic prokaryotes, including bacteria and anaerobic archaea. The clusters in the phylogenetic tree of the HPS protein of M. gastri MB19 and those in the phylogenetic tree of the PHI protein were nearly identical, which implies that these two formaldehyde-fixing genes evolved as a pair. These findings give new insight into the acquisition of the formaldehyde fixation pathway during the evolution of diverse microorganisms.

IgE sensitivity and cross-reactivity to crude and purified mite allergens (Der f 1, Der f 2, Der p 1, Der p 2) in atopic dogs sensitive to Dermatophagoides mite allergens

The present study investigates IgE-reactivity to crude and purified mite allergens by intradermal skin test (IDST), Immunodot method, and ELISA in atopic dogs sensitive to mite allergens, as well as the allergenic cross-reactivity between Dermatophgoides (D) farinae (DF) and D. pteronyssinus (DP) in dogs by IgE-ELISA inhibition. IDST and Immunodot method for crude mite allergens were performed for atopic dogs and 16 atopic dogs showed sensitivity to mite allergens. Of the 16 dogs, all dogs had anti-DF IgE and 11 had anti-DP IgE. We measured specific IgE to purified major allergens (Der f 1, Der f 2, Der p 1, Der p 2). Of the 16 atopic dogs, six had anti-Der f 1 IgE and seven had anti-Der f 2 IgE. Similarly, of the 16 dogs, six had anti-Der p 1 IgE and seven had anti-Der p 2 IgE. However, eight dogs had no specific IgE to these mite allergens. These dogs may be sensitive to other major mite allergens except Der 1 and Der 2. In the dogs that had both anti-DF and DP IgE, IgE binding to DF was greatly inhibited by DP, and reciprocal inhibition was observed. Based on these data, it appears that there is a strong cross-reactivity between DF and DP in dogs. Similarly, a cross-reactivity between DF and DP in purified allergens was also observed. IDST and Immunodot method are useful methods for the diagnosis of atopic diseases in dogs, and ELISA is a useful method for further investigation of IgE-reactivity for the allergens.

Bacillus subtilis yckG and yckF encode two key enzymes of the ribulose monophosphate pathway used by methylotrophs, and yckH is required for their expression

The ribulose monophosphate (RuMP) pathway is one of the metabolic pathways for the synthesis of compounds containing carbon-carbon bonds from one-carbon units and is found in many methane- and methanol-utilizing bacteria, which are known as methylotrophs. The characteristic enzymes of this pathway are 3-hexulose-6-phosphate synthase (HPS) and 6-phospho-3-hexuloisomerase (PHI), neither of which was thought to exist outside methylotrophs. However, the presumed yckG gene product (YckG) of Bacillus subtilis shows a primary structure similar to that of methylotroph HPS (F. Kunst et al., Nature 390:249-256, 1997). We have also investigated the sequence similarity between the yckF gene product (YckF) and methylotroph PHI (Y. Sakai, R. Mitsui, Y. Katayama, H. Yanase, and N. Kato, FEMS Microbiol. Lett. 176:125-130, 1999) and found that the yckG and yckF genes of B. subtilis express enzymatic activities of HPS and PHI, respectively. Both of these activities were concomitantly induced in B. subtilis by formaldehyde, with induction showing dependence on the yckH gene, but were not induced by methanol, formate, or methylamine. Disruption of either gene caused moderate sensitivity to formaldehyde, suggesting that these enzymes may act as a detoxification system for formaldehyde in B. subtilis. In conclusion, we found an active yckG (for HPS)-yckF (for PHI) gene structure (now named hxlA-hxlB) in a nonmethylotroph, B. subtilis, which inherently preserves the RuMP pathway.

[A study of aggravation of atopic dermatitis during Japanese cedar pollen season--correlation with grades of dermatitis on face and Cry j 1 specific IgE]

We studied influence of Japanese cedar pollen (Jcp) on aggravation of atopic dermatitis (AD) during the pollination season. 48.5% of 97 patients with atopic dermatitis showed aggravation of dermatitis during the pollination season and 85% of them had Japanese cedar pollinosis, whereas only 44% of AD patients without the aggravation had the pollinosis. There was no difference of grades of dermatitis on face between the groups with or without the aggravation. Furthermore, we measured specific IgE to Jcp and Cry j 1, a major allergen of Jcp, by ELISA in the sera from the 54 patients with AD. The levels of specific IgE antibodies to both allergens in the group with the pollinosis were significantly higher than in the group without the pollinosis. However, significant difference of those was not recognized between the groups with or without the aggravation of AD. Therefore, our study has suggested that Japanese cedar pollen is likely to be one of causes of seasonal aggravation of AD in individuals sensitized to the pollen, and some other factors, e.g. Jcp-specific T cells, might play an important roll in addition to the Jcp-specific IgE.

Cloning and expression of Der f 6, a serine protease allergen from the house dust mite, Dermatophagoides farinae

House dust mite allergen is thought to be a major cause of asthma. Characterization of these allergen molecules is therefore an important step for the development of effective diagnostic and therapeutic agents against mite-associated allergic disorders. Here we report molecular cloning and expression of the group 6 (chymotrypsin-like) allergen from the house dust mite, Dermatophagoides farinae. Sequencing analysis indicates that cloned cDNA, designated Der f 6, encodes a 279 amino acid polypeptide which conserves a primary structure characteristic for chymotrypsin-like serine proteases found in mammals. Recombinant Der f 6 expressed in Escherichia coli bound IgE in a pool made of 20 sera, and induced histamine release from patients' peripheral blood cells.

Two-dimensional electrophoresis of Malassezia allergens for atopic dermatitis and isolation of Mal f 4 homologs with mitochondrial malate dehydrogenase

The yeast Malassezia furfur is a natural inhabitant of the human skin microflora that induces an allergic reaction in atopic dermatitis. To identify allergens of M. furfur, we separated a crude preparation of M. furfur antigens as discrete spots by 2-D PAGE and detected IgE-binding proteins using sera of atopic dermatitis patients. We identified the known allergens, Mal f 2 and Mal f 3, and determined N-terminal amino acid sequences of six new IgE-binding proteins including Mal f 4. The cDNA and genomic DNA encoding Mal f 4 were cloned and sequenced. The gene was mitochondrial malate dehydrogenase and encoded Mal f 4 composed of 315 amino acids and a signal sequence of 27 amino acids. We purified Mal f 4, which had a molecular mass of 35 kDa from a membrane fraction of a lysate of cultured cells. Thirty of 36 M. furfur-allergic atopic dermatitis patients (83.3%) had elevated serum levels of IgE to purified Mal f 4, indicating that Mal f 4 is a major allergen. There was a significant correlation of the Phadebas RAST unit values of Mal f 4 and the crude antigen, but not between Mal f 4 and the known allergen Mal f 2.

Identification and cloning of two novel allergens from the lipophilic yeast, Malassezia furfur

Two novel allergens, designated Mal f 2 and Mal f 3 according to the WHO/IUIS Allergen Nomenclature Subcommittee recommendation, were isolated from the lipophilic yeast Malassezia furfur cell extracts and the genes coding for those were cloned. Mal f 2 and Mal f 3 had apparent molecular weights of 21 kDa and 20 kDa, respectively, on SDS-PAGE under reducing conditions. The identified cDNA clone of Mal f 2 encoded an open reading frame of 177 amino acid residues. Fifty-one percent identity was found between the Mal f 2 and Mal f 3 sequences. Comparison of the Mal f 2 and Mal f 3 sequences with known protein sequences revealed that they had sequence homology with two peroxisomal membrane proteins of Candida boidinii and an Aspergillus fumigatus allergen, Asp f 3. In RAST, both Mal f 2- and Mal f 3-specific IgE antibodies could be detected in approximately 70 % of sera from M. furfur sensitized patients with atopic dermatitis.

Overproduction of DnaJ in Escherichia coli improves in vivo solubility of the recombinant fish-derived transglutaminase

The overexpression of red sea bream (Pagrus major) transglutaminase (TGase, E.C. 2.3.2.13) in Escherichia coli mostly leads to the accumulation of biologically inactive enzyme. Although the solubility of the gene products could be improved by cultivation at a lower temperature (26-28 degrees C), most of the synthesized TGase was still in the form of insoluble aggregates. The effects of overproduction of molecular chaperones on the intracellular solubility of newly produced recombinant TGase were examined. The overexpression of dnaK or groES/EL did not improve solubility. However, DnaJ greatly increased the solubility of the recombinant TGase, resulting in active enzyme in the presence of calcium ions. Co-expression of dnaK along with dnaJ further increased the content of soluble TGase. Under our experimental conditions, supplementation with both DnaJ and DnaK elevated the TGase activity in the producer cells by roughly 4-fold, compared with the control strain cultured at 30 degrees C. Thus, we found that DnaJ is important in controlling the solubility of protein overproduced in E. coli.

Assay for detecting IgE and IgG antibodies against Candida albicans cell-wall mannan

In the present study, we assayed mannan-specific IgE and IgG antibodies in samples of serum isolated from blood collected from adult patients with bronchial asthma, using a liquid-phase method with a polysaccharide, mannan (Mn), purified from Candida albicans (C. alb), and investigated the relationships of allergenicity among a crude extract of C. alb, purified Mn, and acid protease (AP), The correlations between the titers of anti-Mn A and anti-Mn B IgE and IgG were very strong, and the levels of inhibition of anti-Mn A IgE and IgG reactions by Mn A and Mn B were almost identical. Although no common allergenicity was observed between Mn A and AP because there was no correlation between the titers of anti-Mn A and anti-AP IgE, and no inhibition of the anti-Mn A IgE reaction by AP, both antigens were found to exist in crude C. alb. The level of inhibition of anti-crude C. alb IgG reaction by Mn A or Mn B was about 60%. Approximately 70% inhibition of the anti-Mn A IgE reaction was observed for eight different fungal allergen extracts, but no inhibition was observed for 11 of the other fungal allergen extracts tested. The above results indicate that common antigenicity was observed between Mn A and Mn B in the human IgE and IgG antibody production system, and the cross-allergenicity observed among some fungi was considered to be the result of the common antigenicity of Mn isoforms.

Preventive effect of bedding encasement with microfine fibers on mite sensitization

BACKGROUND

The indoor levels of mite allergens are known to determine the thresholds of sensitization and asthma exacerbation. However, the method for preventing mite sensitization by reducing the levels of house dust mites (HDMs) is not well established.

OBJECTIVE

We investigated whether mite-blocking bedding encasing made from microfine fibers can prevent infants from being sensitized to HDMs.

METHODS

Fifty-seven Japanese infants with atopic dermatitis who had high levels of IgE antibodies against either egg white, cow's milk, or soybean (but not against HDMs) were randomly chosen and divided into two groups. Thirty families of atopic infants (group A) were instructed to decrease HDMs by controlling the indoor environment, including bedding cleaning, whereas 27 families receiving the same instructions (group B) were further guided to use the Allerguard encasing for quilts and mattresses of all family members. We repeatedly examined Der p 1 + Der f 1 in the infants' mattresses and anti-Dermatophagoides farinae (Df) IgE in the infants' sera, and we performed skin prick tests with Df extract for 1 year.

RESULTS

The mite-blocking encasing markedly reduced the levels of Der p 1 + Der f 1 (3.0 microg/g dust for group A vs 0.77 microg/g dust for B, p < 0.001). It also prevented the increase in serum levels of anti-Df IgE (2.5 U/ml for group A vs 0.7 U/ml for group B, p < 0.05) and positive reactions to skin prick testing with Df extract (63% for group A vs 31% for group B, p < 0.02) over 1 year.

CONCLUSION

The bedding encasement with the mite-blocking fibers was effective for preventing atopic infants from being sensitized to HDMs, and it seems to be beneficial to modern busy housekeepers.

Epitope specificity of IgE antibodies to a major allergen (Cry j 1) of Japanese cedar pollen in sera of humans and monkeys with pollinosis

Japanese cedar (Cryptomeria japonica) pollinosis has been reported to occur naturally in Japanese monkeys (Macaca fuscata) as well as humans. Using monoclonal antibodies (mAb) specific to Cry j 1, a major allergen in Japanese cedar pollen, we identified five independent epitopes (EP-1 to EP-5) on the molecule. The epitopes recognized by IgE antibodies in the sera of humans and monkeys with the pollinosis were analysed by an IgE enzyme-linked immunosorbent assay inhibition method with these mAb. In human patients, the mAb to EP-1 strongly blocked the binding of IgE antibodies in all patients' sera to Cry j 1. The reaction patterns of IgE antibodies in monkeys, however, varied among the troops of monkeys. In some troops, the mAb to EP-1 showed a blocking pattern similar to that for human patients. In other troops, mAb to EP-4 and EP-5 blocked binding of IgE. These results indicate that some, but not all, monkeys have antibody responses to the major allergen similar to those of humans.