Studies of bronchial asthma induced by chironomid midges (Diptera) around a hypereutrophic lake in Japan

Genome-wide analyses of ATP-Binding Cassette (ABC) transporter gene family and its expression profile related to deltamethrin tolerance in non-biting midge Propsilocerus akamusi

Non-biting midges are dominant species in aquatic systems and often used for studying the toxicological researches of insecticides. ATP-binding cassette (ABC) transporters represent the largest known members in detoxification genes but is little known about their function in non-biting midges. Here, we selected Propsilocerus akamusi, widespread in urban streams, to first uncover the gene structure, location, characteristics, and phylogenetics of chironomid ABC transporters at genome-scale. Fifty-seven ABC transporter genes are located on four chromosomes, including eight subfamilies (ABCA-H). The ABCC, ABCG, and ABCH subfamilies experienced the duplication events to different degrees. The study showed that expression of the PaABCG17 gene is uniquely significantly elevated, with deltamethrin concentration increasing (1, 4, and 20 ug/L) both in RNA-seq and qPCR results. Additionally, the ABC transporter members of other six chironomids with assembled genomes are first described and used to investigate the characteristic of those living in the different adverse habitats. The ABC transporter frame for Propsilocerus akamusi and its transcriptomic results lay an important foundation for providing valuable resources for understanding the ABC transporter function in insecticide toxification of this species as well as those of other non-biting midges. The PaABCG17 gene is shown to play an important role in deltamethrin detoxification, and it functions need to be further investigated and might be used in the management of insecticide-resistance in chironomid adults.

Respiratory sensitization to insect allergens: Species, components and clinical symptoms

Airborne insect particles have been identified as an important cause of respiratory allergies, including allergic asthma and rhinitis. In the literature, the significance of respiratory exposure to insect particles as a cause of occupational allergy has been well-documented. Indeed, many cases of occupational allergy have been reported including allergy to the larvae of flies and moths in anglers and occupationally exposed workers, to grain pests in bakers or other workers handling grains, and to crickets and/or locusts in researchers and workers in aquaculture companies. Furthermore, the prevalence of sensitization to insect allergens is considerably high among patients with asthma and/or rhinitis who are not occupationally exposed to insects, suggesting the clinical relevance of exposure to insects in indoor and outdoor environmental non-occupational settings. Exposure to cockroaches, a well-studied indoor insect, is associated with cockroach sensitization and the development and exacerbation of asthma. Booklice, another common indoor insect, were recently identified as a significant sensitizer of asthmatic patients in Japan and India, and potentially of asthma patients living in warm and humid climates around the world. Lip b 1 was identified as an allergenic protein contributing to the species-specific sensitization to booklice. Moths are considered a significant seasonal outdoor allergen and their allergens are considered to have the highest sensitization rate among Japanese patients. However, other than cockroaches, allergenic insect proteins contributing to sensitization have not been fully characterized to date.

A chromosome level genome assembly of Propsilocerus akamusi to understand its response to heavy metal exposure

Chironomidae species are universally used for studying the impact of pollutants in aquatic systems. The nonbiting midge Propsilocerus akamusi is often found in urban streams and is suitable for use as a toxicological bioindicator. However, few studies have previously examined metal stress in this species. We sequenced the genome of this urban midge to address this question. Here, we present the first chromosome-level genome of P. akamusi, obtained from Illumina short-read and PacBio long-read sequences with Hi-C technology. The size of the very small assembled genome was 85.83 Mb with a contig N50 of 6.2 Mb and a scaffold N50 of 26.1 Mb. This assembly revealed significant expansion of haemoglobin (Hb) genes, some of which formed large tandem repeats. Transcriptomic studies for copper tolerance identified four genes in the tandem array that were highly expressed, all of which presented intron loss. This characteristic might highlight the potential role of Hb genes in copper tolerance. Additionally, detoxification genes, chemosensory genes and heat shock protein genes of this midge were identified, some of which are associated with metal stress. The high-quality assembled genome of P. akamusi and the transcriptomic analyses provide new insight into the molecular mechanisms of heavy metal stress. Our comparison of the P. akamusi genome with other dipteran genomes provides valuable resources for understanding the evolutionary history, genetics, and ecology of this species as well as those of other midges.

Minute and diverse in fossil sticky stuff: Tanytarsini (Diptera: Chironomidae) from early Eocene Indian Cambay amber

We here present a pioneering systematic review of fossil dipterans of the tribe Tanytarsini (family Chironomidae) discovered in Indian amber from Cambay. The specimens examined belong to five species: Gujaratomyia miripes,Stempellina stebneri sp. nov., Stempellinella pollex sp. nov., Tanytarsus forfex sp. nov. andTanytarsus ramus sp. nov., which are described. All species belong to the oldest known Tanytarsini and come from the Cambay shale formation in Tadkeshwar, dated to the early Eocene (~54 Mya). Displaying unusual characters/structures of diagnostic and phylogenetic importance, the specimens studied are discussed against the background of the evolution and systematics of the oldest fossil (Eocene) and extant representatives in the tribe. An updated checklist and key to the identification of genera and species of Tanytarsini from Eocene amber is also provided. The spectral characteristics and physical properties of Cambay amber are similar to those of glessite resins, which are discussed in detail in order to substantiate the identity of the amber and the origin of the inclusions studied.

A review on Respiratory allergy caused by insects

Hypersensitivity or allergy encompasses a wide range of immunological reactions that generally have adverse consequences involving one or many organ systems of the body. Allergens are usually glycoprotein or chemically complex low molecular weight substances. The common allergens include pollen, fungal spores, house dust mite and house dust, animal danders, drugs, foods, insect emanations, and detritus, etc. Information on the role of insects in respiratory allergy is increasing in the literature. There are about 30 million living species of insects. These insects can broadly be classified as stinging insects, biting insects and non-stinging and non-biting insects. All materials form insets namely wings, scales, saliva; dried feces and venom can cause allergic diseases, such as rhinitis, conjunctivitis, asthma and urticaria. There are wide varieties of insects such as moths, butterflies, bees, wasps, hornets, yellow jackets, flies, beetles, cockroaches, and mosquitoes. Exposure to emanations and detritus of these insects may lead to several allergies in some genetically predisposed individuals. Therefore, it is of interest to review allergies caused by various insect's stings and bites and their adverse effect on the human body.

Phototaxis of Propsilocerus akamusi (Diptera: Chironomidae) From a Shallow Eutrophic Lake in Response to Led Lamps

A study on the attraction of adult Propsilocerus akamusi midges to different-colored light traps was carried out from October 21 to November 15, 2013. The 6 colored lights used in light-emitting diode (LED) lamps were white, green, red, blue, amber, and ultraviolet (UV). The UV lamp attracted the most P. akamusi, followed by green, white, blue, amber, and red. A white pulsed LED light attracted only half the number of midges as did a continuous-emission white LED light. The result indicated that manipulation of light color, considering that the red LED light and/or pulsed LED light are not as attractive as the other colors, may be appropriate for the development of an overall integrated strategy to control nuisance P. akamusi in the Lake Suwa area.

Group 10 allergens (tropomyosins) from house-dust mites may cause covariation of sensitization to allergens from other invertebrates

Group 10 allergens (tropomyosins) have been assumed to be a major cause of cross-reactivity between house-dust mites (HDMs) and other invertebrates. Despite all of the published data regarding the epidemiology, percent IgE binding and level of sensitization in the population, the role of tropomyosin as a cross-reactive allergen in patients with multiple allergy syndrome still remains to be elucidated. Homology between amino acid sequences reported in allergen databases of selected invertebrate tropomyosins was determined with Der f 10 as the reference allergen. The 66.9 and 54.4% identities were found with selected crustacean and insect species, respectively, whereas only 20.4% identity was seen with mollusks. A similar analysis was performed using reported B-cell IgE-binding epitopes from Met e1 (shrimp allergen) and Bla g7 (cockroach allergen) with other invertebrate tropomyosins. The percent identity in linear sequences was higher than 35% in mites, crustaceans, and cockroaches. The polar and hydrophobic regions in these groups were highly conserved. These findings suggest that tropomyosin may be a major cause of covariation of sensitization between HDMs, crustaceans, and some species of insects and mollusks.

Survey on negative impact of chironomid midges (Diptera) on bronchial asthmatic patients in a hyper-eutrophic lake area in Japan

Chironomid midges have been revealed to be a hazardous inhalant antigen of bronchial asthma. To determine the awareness of the negative impact of chironomid midges (Chironomus plumosus and Propsilocerus akamusi) among patients, a questionnaire survey of 118 patients in the Lake Suwa area and in the Matsumoto area was conducted from early September to mid-November of 1993. The life style was almost the same among the asthmatic patients in the Lake Suwa area and in the Matsumoto area, but the reactions to the nuisance differed significantly from each other. Although "Flight density" was higher in the Lake Suwa area (p < 0.01) than that in the Matsumoto area, 25.5% of the patients in the Lake Suwa area and 9.1% of those in the Matsumoto area answered "Endurable" (p < 0.01). Further follow-up studies including prick tests, intradermal tests and provocation tests should be conducted for patients who complained a strong allergic reaction.

Fishing for allergens: bloodworm-induced asthma

Hypersensitivity to bloodworms (chironomid larvae) leading to asthma and other related allergic disorders is becoming common in individuals who keep or work with fish due to the increased use of bloodworms as fish food or bait.

Arthropod allergens and human health

Many species of arthropods are the sources of potent allergens that sensitize and induce IgE-mediated allergic reactions in humans. Most of these arthropod allergens are proteins, and the allergic response mechanism to these allergens is the same as it is for allergens from other sources such as plant pollens, molds, and foods. Aside from ingestion of crustaceans (shrimp, lobster), among arthropods, humans have the greatest contact with insects and mites, and as a result allergies to these two groups of arthropods have been the most frequently reported. Because of the large number of people affected by allergic reactions to stinging insects, cockroaches, and dust mites, many allergens of these organisms have been extensively studied, purified, and immunobiochemically characterized and for some recombinant allergens, produced. Cocktails of these recombinant allergens have the potential for use in diagnosis and immunotherapy. In this chapter, we review the insects and mites that induce allergic reactions. Where the information exists, the immunobiochemical characterization of the allergens and the frequency of sensitivity or clinical reactivity in the human population are also reviewed. As background, the beginning of this review includes sections that define allergens, explain the allergic reaction mechanism, and describe the methods for naming allergens.

Occupational asthma caused by champignon flies

BACKGROUND

Occupational bronchial asthma in mushroom (champignon) workers is unusual, although reports on it appeared in 1938 and 1951; we have not found any others since those dates. Here we report the case of a 52-year-old man who works as a champignon cultivator. He suffered rhinoconjunctivitis and asthma attacks whenever he entered the champignon culture caves. We studied flies as a possible antigen source. We collected these insects from the growing sites in order to identify them, and then prepare an extract; the samples turned out to be of two families of insects of the order Diptera, 98% from the Phoridae family (Brachycera suborder) and 2% from the Sciaridae (Nematocera suborder).

METHODS

Skin prick tests, conjunctival provocation tests, serum specific IgE, specific IgE-binding fractions in immunoblotting, and monitoring of PEFR (at work and off work) were performed.

RESULTS

IgE-mediated hypersensitivity to these flies was demonstrated by skin prick test, conjunctival provocation test, serum specific IgE, and IgE-binding fractions in immunoblotting. Monitoring of PEFR both at work and off work showed a clear relationship between symptoms, or fall in PEFR, and the workplace.

CONCLUSIONS

We report the case of a patient suffering from asthma and rhinoconjunctivitis caused by hypersensitivity to fly proteins.