Identification and characterization of an arginine kinase as a major allergen from silkworm (Bombyx mori) larvae

Bom m 9 from Bombyx mori is a novel protein related to asthma

The silkworm (Bombyx mori) can cause severe IgE-mediated allergic disease, however, the mechanism remains unclear. The aim of this study was to investigate the immunologic mechanism by which silkworms induce allergy. Whole silkworm pupa proteins were separated by SDS-PAGE and 2-D PAGE. Then, IgE-binding proteins were detected by immunoblotting with sera of patients having an allergy to Bombyx mori. After tryptic digestion, the peptides of IgE-binding proteins were analyzed by matrix-assisted laser desorption ionization tandem time-of-flight mass spectrometry or tandem mass spectrometry. Database searches were used to identify allergens in silkworm pupa, after which Bom m 9 was to construct an asthma model. Thus, in the current study, a mouse asthma model was constructed with Bom m 9.

Allergenic Characterization of 27-kDa Glycoprotein, a Novel Heat Stable Allergen, from the Pupa of Silkworm, Bombyx mori

Boiled silkworm pupa is a traditional food in Asia, and patients with silkworm pupa food allergy are common in these regions. Still now only one allergen from silkworm, arginine kinase, has been identified. The purpose of this study was to identify novel food allergens in silkworm pupa by analyzing a protein extract after heat treatment. Heat treated extracts were examined by proteomic analysis. A 27-kDa glycoprotein was identified, expressed in Escherichia coli, and purified. IgE reactivity of the recombinant protein was investigated by ELISA. High molecular weight proteins (above 100 kDa) elicited increased IgE binding after heat treatment compared to that before heat treatment. The molecular identities of these proteins, however, could not be determined. IgE reactivity toward a 27-kDa glycoprotein was also increased after heating the protein extract. The recombinant protein was recognized by IgE antibodies from allergic subjects (33.3%). Glycation or aggregation of protein by heating may create new IgE binding epitopes. Heat stable allergens are shown to be important in silkworm allergy. Sensitization to the 27-kDa glycoprotein from silkworm may contribute to elevation of IgE to silkworm.

Processo e cargas de trabalho e a saúde dos trabalhadores na sericicultura: uma revisão

Resumo Introdução: sericicultura é a atividade de criação do bicho-da-seda (Bombyx mori). No Brasil é geralmente desenvolvida por pequenos agricultores. Objetivo: analisar a relação entre processo de trabalho e saúde-doença dos sericicultores. Métodos: revisão integrativa de literatura conduzida nas bases Medline, SciELO e Scopus e no banco de teses e de periódicos da CAPES. Resultados: quinze trabalhos atenderam aos critérios estabelecidos. Em nove desses estudos foi possível identificar o processo e as cargas de trabalho e nos outros seis, as doenças relacionadas à atividade. Identificaram-se como cargas de trabalho: físicas – umidade, ventilação, temperatura e intempéries; químicas – uso de adubos, formol, cal hidratada e fungicida; mecânicas – riscos de acidentes com equipamentos; orgânicas – fungos, bactérias, vírus e insetos; fisiológicas – esforço físico, trabalho noturno, jornadas prolongadas; psíquicas – ritmo e intensidade de trabalho, responsabilidade pela tarefa. Também foram relacionadas doenças respiratórias, alergias, irritação nos olhos, feridas, dores nas costas e de cabeça. Conclusão: apesar dos potenciais problemas relacionados à saúde dos trabalhadores da sericicultura, no Brasil não foram identificadas pesquisas voltadas especificamente a esse tema, mostrando a necessidade de realização de estudos para suprimir essa lacuna.

Influence of processing and in vitro digestion on the allergic cross-reactivity of three mealworm species

Edible insects are currently being evaluated as an alternative and more sustainable protein source for humans. The introduction of new food sources can lead to development of novel allergies. Because in the Western world, insects are unlikely to be consumed raw, it is important to know how processing and in vitro digestion might influence their allergenicity. Three edible mealworm species (Tenebrio molitor, Zophobas atratus and Alphitobius diaperinus) subjected to processing and in vitro digestion were analysed for IgE cross-reactivity. Immunoblot and MALDI-MS/MS analyses revealed that IgE from crustaceans or House dust mite (HDM) allergic patients showed cross-reactivity to mealworm tropomyosin or α-amylase, hexamerin 1B precursor and muscle myosin, respectively. Heat processing as well as in vitro digestion did diminish, but not eliminate, HDM or tropomyosin IgE cross-reactivity. Results show that individuals allergic to HDM or crustaceans might be at risk when consuming mealworms, even after heat processing.

Cross-reactivity between aeroallergens and food allergens

In patients with respiratory allergy, cross-reactivity between aeroallergens and foods may induce food allergy, symptoms ranging from oral allergy syndrome to severe anaphylaxis. Clinical entities due to IgE sensitization to cross-reactive aeroallergen and food allergen components are described for many sources of plant origin (pollen-food syndromes and associations, such as birch-apple, cypress-peach and celery-mugwort-spice syndromes, and mugwort-peach, mugwort-chamomile, mugwort-mustard, ragweed-melon-banana, goosefoot-melon associations), fungal origin (Alternaria-spinach syndrome), and invertebrate, mammalian or avian origin (mite-shrimp, cat-pork, and bird-egg syndromes). Clinical cases of allergic reactions to ingestion of food products containing pollen grains of specific plants, in patients with respiratory allergy to Asteraceae pollen, especially mugwort and ragweed, are also mentioned, for honey, royal jelly and bee polen dietary supplements, along with allergic reactions to foods contaminated with mites or fungi in patients with respiratory allergy to these aeroallergens. Medical history and diagnosis approach may be guided by the knowledge about the diverse cross-reacting allergens involved, and by the understanding of these clinical entities which may vary significantly or may be overlapping. The association between primary IgE sensitization with respiratory symptoms to inhaled allergens and food allergy due to cross-reactive allergen components is important to assess in allergy practice. The use of molecular-based diagnosis improves the understanding of clinically relevant IgE sensitization to cross-reactive allergen components from aeroallergen sources and foods.

The Inhibitory Effects of Cu(2+) on Exopalaemon carinicauda Arginine Kinase via Inhibition Kinetics and Molecular Dynamics Simulations

We studied the Cu(2+)-mediated inhibition and aggregation of Exopalaemon carinicauda arginine kinase (ECAK). We found that Cu(2+) significantly inactivated ECAK activity and double-reciprocal kinetics demonstrated that Cu(2+) induced noncompetitive inhibition of arginine and ATP (IC50 = 2.27 ± 0.16 μM; K i for arginine = 13.53 ± 3.76; K i for ATP = 4.02 ± 0.56). Spectrofluorometry results showed that Cu(2+) induced ECAK tertiary structural changes including the exposure of hydrophobic surfaces that directly induced ECAK aggregation. The addition of osmolytes such as glycine and proline successfully blocked ECAK aggregation induced by Cu(2+) and recovered ECAK activity. We built a 3D structure for ECAK using the ECAK ORF gene sequence. Molecular dynamics (MD) and docking simulations between ECAK and Cu(2+) were conducted to elucidate the binding mechanisms. The results showed that Cu(2+) blocked the entrance to the ATP active site; these results are consistent with the experimental result that Cu(2+) induced ECAK inactivation. Since arginine kinase (AK) plays an important role in cellular energy metabolism in invertebrates, our study can provide new information about the effect of Cu(2+) on ECAK enzymatic function and unfolding, including aggregation, and the protective effects of osmolytes on ECAK folding to better understand the role of the invertebrate ECAK metabolic enzyme in marine environments.

Proteomic and immunological identification of two new allergens from silkworm (Bombyx mori L.) pupae

This study explored food allergy caused by eating silkworm (Bombyx mori L.) pupae, a traditionally accepted food and animal feed in East and Southeast Asia, and identified two new allergens by proteomic and immunological methods. Proteins isolated from silkworm pupae were separated by two-dimensional gel electrophoresis (2-DE); pooled sera from patients allergic to silkworm pupa proteins were used to detect immunoglobulin E (IgE)-binding proteins by western blotting, and allergens specific for silkworm pupa consumption-caused allergy were visualised with the ECL reagents. The selected allergen proteins were further identified by matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF-MS) analysis. Finally, chitinase and paramyosin were identified as silkworm pupa proteins showing strong immunoglobulin (IgE)-binding reaction. Analysis of the sequence homology of the two proteins using the AllergenOnline database indicated that chitinase and paramyosin shared 24.8% and 62.8% sequence homology with known allergens Der f 18 (Dermatophagoides farinae) and Der p 11 (Dermatophagoides pteronyssinus), respectively. Our results shed light on the understanding and treatment of silkworm pupa allergy.

Identification of novel allergen in edible insect, Gryllus bimaculatus and its cross-reactivity with Macrobrachium spp. allergens

Edible insects have recently been promoted as a source of protein and have a high nutrition value. Identification of allergens and cross-reactivity between Macrobrachium spp. and the field cricket (Gryllus bimaculatus) is necessary for food safety control and to assist in the diagnosis and therapy of allergy symptoms. Denaturing polyacrylamide gel electrophoresis (SDS-PAGE) was used to separate proteins. Allergens were determined and identified by IgE-immunoblotting with pooled sera from prawn-allergic patients (n=16) and LC-MS/MS. Arginine kinase (AK) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) were determined as the important allergens in muscle of Macrobrachium rosenbergii whereas, hemocyanin (HC) was identified as an allergen in Macrobrachium spp. The allergens in Macrobrachium lanchesteri were identified as AK and HC. In addition, hexamerin1B (HEX1B) was identified as a novel and specific allergen in G. bimaculatus. The important allergen in G. bimaculatus and Macrobrachium spp. is AK and was found to cross-react between both species.

Isolation of arginine kinase from Apis cerana cerana and its possible involvement in response to adverse stress

Arginine kinases (AK) in invertebrates play the same role as creatine kinases in vertebrates. Both proteins are important for energy metabolism, and previous studies on AK focused on this attribute. In this study, the arginine kinase gene was isolated from Apis cerana cerana and was named AccAK. A 5'-flanking region was also cloned and shown to contain abundant putative binding sites for transcription factors related to development and response to adverse stress. We imitated several abiotic and biotic stresses suffered by A. cerana cerana during their life, including heavy metals, pesticides, herbicides, heat, cold, oxidants, antioxidants, ecdysone, and Ascosphaera apis and then studied the expression patterns of AccAK after these treatments. AccAK was upregulated under all conditions, and, in some conditions, this response was very pronounced. Western blot and AccAK enzyme activity assays confirmed the results. In addition, a disc diffusion assay showed that overexpression of AccAK reduced the resistance of Escherichia coli cells to multiple adverse stresses. Taken together, our results indicated that AccAK may be involved of great significance in response to adverse abiotic and biotic stresses.

A hypothetical model of crossing Bombyx mori nucleopolyhedrovirus through its host midgut physical barrier

Bombyx mori nucleopolyhedrovirus (BmNPV) is a primary pathogen of silkworm (B. mori) that causes severe economic losses each year. However, the molecular mechanisms of silkworm-BmNPV interactions, especially the silkworm proteins that can interact with the virus, are still largely unknown. In this study, the total and membrane proteins of silkworm midguts were displayed using one- and two-dimensional electrophoresis. A virus overlay assay was used to detect B. mori proteins that specifically bind to BmNPV particles. Twelve proteins were located and identified using mass spectrometry, and the different expression of the corresponding genes in BmNPV susceptible and resistant silkworm strains also indicated their involvement in BmNPV infection. The 12 proteins are grouped based on their potential roles in viral infection, for example, endocytosis, intracellular transportation, and host responses. Based on these results, we hypothesize the following: I) vacuolar ATP synthase catalytic subunit A and subunit B may be implicated in the process of the membrane fusion of virus and the release of the nucleocapsid into cytoplasm; II) actin, enolase and phosphoglycerate kinase are cytoskeleton associated proteins and may play an important role in BmNPV intracellular transportation; III) mitochondrial prohibitin complex protein 2, ganglioside-induced differentiation-associated protein, calreticulin, regucalcin-like isoform X1 and 60 kDa heat shock protein are involved in cell apoptosis regulation during BmNPV infection in larvae midguts; IV) ribosomal P0 may be associated with BmNPV infection by regulating gene expression of BmNPV; V) arginine kinase has a role in the antiviral activities against BmNPV. Our work should prove informative by providing multiple protein targets and a novel direction to investigate the molecular mechanisms of the interactions between silkworms and BmNPV.

Co-sensitization to silkworm moth (Bombyx mori) and 9 inhalant allergens among allergic patients in Guangzhou, Southern China

Objectives

This study aimed to investigate the profile of sensitization to silkworm moth (Bombyx mori) and other 9 common inhalant allergens among patients with allergic diseases in southern China.

Methods

A total of 175 patients were tested for serum sIgE against silkworm moth in addition to combinations of other allergens: Dermatophagoides pteronyssinus, Dermatophagoides farinae, Blomia tropicalis, Blattella germanica, Periplaneta americana, cat dander, dog dander, Aspergillus fumigatus and Artemisia vulgaris by using the ImmunoCAP system. Correlation between sensitization to silkworm moth and to the other allergens was analyzed.

Results

Of the 175 serum samples tested, 86 (49.14%) were positive for silkworm moth sIgE. With high concordance rates, these silkworm moth sensitized patients were concomitantly sensitized to Dermatophagoides pteronyssinus (94.34%), Dermatophagoides farinae (86.57%), Blomia tropicalis (93.33%), Blattella germanica (96.08%), and Periplaneta americana (79.41%). Moreover, there was a correlation in serum sIgE level between silkworm moth and Dermatophagoides pteronyssinus (r = 0.518), Dermatophagoides farinae (r = 0.702), Blomia tropicalis (r = 0.701), Blattella germanica (r = 0.878), and Periplaneta americana (r = 0.531) among patients co-sensitized to silkworm moth and each of these five allergens.

Conclusion

In southern Chinese patients with allergic diseases, we showed a high prevalence of sensitization to silkworm moth, and a co-sensitization between silkworm moth and other five common inhalant allergens. Further serum inhibition studies are warranted to verify whether cross-reactivity exists among these allergens.

House dust mite (Der p 10) and crustacean allergic patients may react to food containing Yellow mealworm proteins

SCOPE

Due to the imminent growth of the world population, shortage of protein sources for human consumption will arise in the near future. Alternative and sustainable protein sources (e.g. insects) are being explored for the production of food and feed. In this project, the safety of Yellow mealworms (Tenebrio molitor L.) for human consumption was tested using approaches as advised by the European Food Safety Authority for allergenicity risk assessment.

METHODS AND RESULTS

Different Yellow mealworm protein fractions were prepared, characterised, and tested for cross-reactivity using sera from patients with an inhalation or food allergy to biologically related species (House dust mite (HDM) and crustaceans) by immunoblotting and basophil activation. Furthermore, the stability was investigated using an in vitro pepsin digestion test. IgE from HDM- and crustacean allergic patients cross-reacted with Yellow mealworm proteins. This cross-reactivity was functional, as shown by the induction of basophil activation. The major cross-reactive proteins were identified as tropomyosin and arginine kinase, which are well known allergens in arthropods. These proteins were moderately stable in the pepsin stability test.

CONCLUSION

Based on these cross-reactivity studies, there is a realistic possibility that HDM- and crustacean allergic patients may react to food containing Yellow mealworm proteins.

Molecular and biochemical characterisation of arginine kinases in Haemonchus contortus and Teladorsagia circumcincta

Full length cDNA encoding arginine kinases (AK) were cloned from Teladorsagia circumcincta (TcAK) and Haemonchus contortus (HcAK). The TcAK and HcAK cDNA (1080 bp) encoded 360 amino acid proteins. The predicted amino acid sequence showed 99% similarity with each other and 94% with a Caenorhabditis elegans AK. Soluble N-terminal His-tagged AK proteins were expressed in Escherichia coli strain BL21, purified and characterised. All binding sites were completely conserved in both proteins. The recombinant TcAK and HcAK had very similar kinetic properties: K(m) arginine was 0.35 mM, K(m) ATP was 0.8-0.9 mM and the pH optima were pH 7.5. Arginine analogues strongly inhibited recombinant enzyme activities (up to 80%), whilst other amino acids decreased activities by a maximum of 20%. TcAK and HcAK are potential vaccine candidates because of the strong antigenicity of invertebrate phosphagens and kinases and presence in metabolically active parts of the worm.

Sensitization to Per a 2 of the American cockroach correlates with more clinical severity among airway allergic patients in Taiwan

BACKGROUND

In Taiwan, 57.5% of asthmatic patients are allergic to cockroaches, which are a major indoor allergen for immunoglobulin E (IgE)-mediated respiratory diseases.

OBJECTIVE

To determine whether sensitization to different cockroach allergenic components correlates with different clinical manifestations and severities.

METHODS

The complementary DNAs (cDNAs) encoding for Per a 1 through 7 and Per a 9 were generated by reverse transcription polymerase chain reaction and cloned into the Escherichia coli expression system. Sixty-four subjects were divided into 3 groups based on the clinical severity of their allergic reaction: those with persistent asthma and rhinitis (AS), those with allergic rhinitis only (AR), and the nonallergic controls (NA). Serum levels of interleukin-8 (IL-8), monocyte chemotactic protein-1 (MCP-1), chemokine (C-C motif) ligand 20 (CCL-20), and granulocyte macrophage colony-stimulating factor (GM-CSF) were measured, and the binding frequencies to each recombinant allergen were examined.

RESULTS

Serum levels of IL-8, MCP-1, and CCL-20 were significantly higher in the AS group than in the AR and NA groups. The numbers of IgE-binding allergens did not correlate with the clinical severity of airway allergy to cockroaches. However, 81% in the AS group had IgE-binding activity to Per a 2, which was significantly higher than that of the AR group (45%, P < .05). In contrast, 80% of AR patients had IgE-binding activity to Per a 9 compared with only 28.5% of AS patients (P < .01).

CONCLUSION

Allergens from American cockroaches do not have equal importance in terms of pathogenicity. Sensitization to Per a 2 correlates with more severe airway allergy and elevated proinflammatory chemokines. This may help in selecting target allergens for component resolved diagnosis and immunotherapeutic agents.

Characterization of allergens isolated from the freshwater fish blunt snout bream (Megalobrama amblycephala)

Fish are an important source of dietary protein for humans throughout the world. However, they are recognized as one of the most common food allergens and pose a serious health problem in countries where fish consumption is high. Many marine fish allergens have been extensively studied, but relatively little is known about freshwater fish allergens. This study identified two main allergens from blunt snout bream (Megalobrama amblycephala), a freshwater fish widely consumed in China. Sera from 11 patients with convincing clinical history of blunt snout bream allergy were utilized in IgE immunoblot analysis to identify prominent allergens. Several blunt snout bream proteins revealed specific binding to serum IgE, with the 47 and 41 kDa proteins being the most immunodominant among them. Two-dimensional gel electrophoresis (2D SDS-PAGE) enabled resolution of the 47 and 41 kDa proteins into several protein spots with distinct isoelectric points. 2D SDS-PAGE along with IgE immunoblot analysis further confirmed the strong reactivity of these protein spots with the pooled sera from blunt snout bream-sensitive patients. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis of the peptides generated by trypsin digestion of the different spots corresponding to the 47 and 41 kDa proteins indicated that these spots were isoforms of enolase and muscle creatine kinase, respectively. The potential allergenicity of these proteins was further verified by an bioinformatics approach using the full-length and 80 amino acid sliding window FASTA searches, which revealed a significant amino acid sequence homology between blunt snout bream allergens and several known inhaled and crustacean allergens.

Arginine kinase is highly expressed in a resistant strain of silkworm (Bombyx mori, Lepidoptera): Implication of its role in resistance to Bombyx mori nucleopolyhedrovirus

A gene encoding Bombyx mori arginine kinase (BmAK) has been indentified differentially expressed in the midguts of Bombyx mori strain NB which is resistant to nucleopolyhedrovirus (BmNPV), strain 306 which is susceptible to NPV and a near isogenic line BC(8) with similar genetic background to 306 but resistant to NPV by two-dimensional gel electrophoresis (2-DE). In this study, we characterized the expression profiles of BmAK using RT-PCR and real-time quantitative PCR. The expression level of BmAK fluctuated in various developing stage and various tissue. Remarkably, the expression level of BmAK increased more than 10-fold 24 hours post inoculation (h p.i.) of NPV in strain NB and BC(8), while such increment was abraded in strain 306 although the basal expression level of BmAK in strain 306 was higher than that of strain NB and BC(8). Western blotting analysis using polyclonal antibody against BmAK verified such observation, and immunofluoresence analysis indicated for the first time that BmAK was mainly located to the cytoplasm or some structures in cytoplasm. These findings suggest that arginine kinase is involved in the antiviral process of Bombyx mori larvae against NPV infection.