Mite Bodies Research Articles

A novel Bartonella-like bacterium forms an interdependent mutualistic symbiosis with its host, the stored-product mite Tyrophagus putrescentiae.

A novel Bartonella-like symbiont (BLS) of Tyrophagus putrescentiae was characterized. BLS formed a separate cluster from the Bartonella clade together with an ant symbiont. BLS was present in mite bodies (103 16S DNA copies/mite) and feces but was absent in eggs. This indicated the presence of the BLS in mite guts. The BLS showed a reduction in genome size (1.6 Mb) and indicates gene loss compared to Bartonella apis. The BLS can be interacted with its host by using host metabolic pathways (e.g., the histidine and arginine metabolic pathways) as well as by providing its own metabolic pathways (pantothenate and lipoic acid) to the host, suggesting the existence of a mutualistic association. Our experimental data further confirmed these potential mutualistic nutritional associations, as cultures of T. putrescentiae with low BLS abundance showed the strongest response after the addition of vitamins. Despite developing an arguably tight dependency on its host, the BLS has probably retained flagellar mobility, as evidenced by the 32 proteins enriched in KEGG pathways associated with flagellar assembly or chemotaxis (e.g., fliC, flgE, and flgK, as highly expressed genes). Some of these proteins probably also facilitate adhesion to host gut cells. The microcin C transporter was identified in the BLS, suggesting that microcin C may be used in competition with other gut bacteria. The 16S DNA sequence comparison indicated a mite clade of BLSs with a broad host range, including house dust and stored-product mites. Our phylogenomic analyses identified a unique lineage of arachnid specific BLSs in mites and scorpions.IMPORTANCEA Bartonella-like symbiont was found in an astigmatid mite of allergenic importance. We assembled the genome of the bacterium from metagenomes of different stored-product mite (T. putrescentiae) cultures. The bacterium provides pantothenate and lipoic acid to the mite host. The vitamin supply explains the changes in the relative abundance of BLSs in T. putrescentiae as the microbiome response to nutritional or pesticide stress, as observed previously. The phylogenomic analyses of available 16S DNA sequences originating from mite, scorpion, and insect samples identified a unique lineage of arachnid specific forming large Bartonella clade. BLSs associated with mites and a scorpion. The Bartonella clade included the previously described Ca. Tokpelaia symbionts of ants.

Morphological features of the causative agent of chorioptic mange isolated from cattle

Providing veterinary care against parasitic diseases is one of the factors that affect the possibility of effective and profitable introduction of the livestock sector. Chorioptic mange is one of the globally spread invasive diseases of cattle caused by persistent ectoparasites. The diagnosis of chorioptosis is based on the microscopic detection of mites in scrapings from the skin of the affected animal with mandatory identification of the parasites. The aim of the research was to investigate the morphological features and metric parameters of Chorioptes mites isolated from cattle. Mites isolated from cattle were morphometrically identified as Chorioptes texanus. Morphological features of male Ch. texanus mites include peculiarities in the structure of the opisthosomal lobes and of the setae located on the opisthosomal lobes, opisthosoma and tarsus of leg III. 14 morphometric parameters characterizing the general structure of the body (length, width and their ratio, length and width of the gnathosoma, length of the idiosoma, proterosoma, podosoma, propodosoma, metapodosoma, hysterosoma, opisthosoma, length and width of the propodosomal shield) were identified and suggested for use in identification of male and female Ch. texanus. In male mites of this species, 5 additional parameters were also determined, which describe the length and width of the opisthomal lobes, their ratio, the diameter of the adanal suckers and the distance between them. The morphological features, location and length of 6 setae, which are species-specific in Chorioptes mites, namely 4 setae of the opisthosomal lobe, 1 opisthosomal seta, 1 ventral seta of tarsus III, were described. The parameters of Ch. texanus eggs in the bodies of female mites and on the body of the host animal were determined. The scientific data obtained in this study expand the already existing data on the differential identification of Ch. texanus mites and proves their parasitism in cattle on the territory of Ukraine.

Hematology of Liolaemus pacha (Iguania: Liolaemidae) and its relationship with mite infestation, reproductive period and body condition.

Variations in hematological profile in reptiles can be caused by multiple factors, including parasites presence. Our goals were to identify and morphologically describe blood cells of Liolaemus pacha and analyze their relationship with sex, body condition, individual reproductive/post-reproductive period and mite infestation. Blood smear analyses do not indicate the presence of hemoparasites, suggesting that the mites Neopterygosoma do not serve as vectors for these organisms, as has been proposed for other genera of ectoparasitic mites. In post-reproductive period, there was a reduction in specimens' body condition and a higher leukocyte count in uninfected lizards. This could be a consequence of the testosterone effects, in higher concentration during the reproductive season, which can increase the metabolic rate, decreasing feeding rate. Infested and non-infested lizards showed no differences in body condition, as well as in leukocyte count, hence the host's immune system could be developing infestation tolerance. Infested specimens had a higher count of monocytes, thrombocytes, heterophils and lymphocytes. Based on cells function, mites' effect could be associated with inflammatory processes, allergic reactions or infectious diseases. These results suggested a complex interaction between lizards' hematological parameters and factors associated to ectoparasites or body conditions. We consider this work as a diagnostic tool for genus Liolaemus, to evaluate health quality, with relevance to the conservation or management of this lizard's genus.

The internal anatomy of the scale mite Pterygosoma pseudotrapelus (Trombidiformes, Pterygosomatidae)

This study is the first description of the internal anatomy of the scale mites using the example of parasitizing Pterygosoma pseudotrapelus (Bochkov et al., 2009) – a parasite of agamid lizards. Data on histology of the integument, digestive tract, excretory organs, prosomal glands, tracheae, and body-cavity tissues of females, supplemented by the ultrastructure of major organs, are discussed in comparison with information from other groups of the Acari. The female reproductive system was examined only at the light microscopic level. The shape of mite body is adapted to the existence under the scales of the reptile, where the parasite spends its entire life. The width of the adult females is nearly twice their length, resulting in the eccentric position of certain internal organs: the large reproductive system is oriented across the body, so that the ovary with developing oocytes occupies the right side of the idiosoma, while oviduct, seminal receptacle, and vagina are displaced to the left. The structure of the tracheal system and the podocephalic complex of P. pseudotrapelus is similar to that of Tetranychoidea, a group also regarded as one of the lower taxa in the cohort Raphignathina. A number of previously unknown primitive traits identified in the study confirm a relatively basal position of the scale mites within Raphignathina. These include a panoistic ovary, the postcolon instead of an excretory organ of more advanced forms, and 2 pairs of podocephalic acinar glands against the general trend of their reduction in this cohort. An unpaired tracheal gland was found independent from the podocephalic system. The coxal glands lack a filtering sacculus and their epithelium forms mutual interdigitations with the surrounding modified ventricular wall.

Predicting Blomia tropicalis allergens using a multiomics approach.

The domestic mite Blomia tropicalis is a major source of allergens in tropical and subtropical regions. Despite its great medical importance, the allergome of this mite has not been sufficiently studied. Only 14 allergen groups have been identified in B. tropicalis thus far, even though early radioimmunoelectrophoresis techniques (27 uncharacterized allergen complexes) and comparative data based on 40 allergen groups officially recognized by the World Health Organization (WHO)/IUIS in domestic astigmatid mites suggest the presence of a large set of additional allergens. Here, we employ a multiomics approach to assess the allergome of B. tropicalis using genomic and transcriptomic sequence data and perform highly sensitive protein abundance quantification. Among the 14 known allergen groups, we confirmed 13 (one WHO/IUIS allergen, Blo t 19, was not found) and identified 16 potentially novel allergens based on sequence similarity. These data indicate that B. tropicalis shares 27 known/deduced allergen groups with pyroglyphid house dust mites (genus Dermatophagoides). Among these groups, five allergen-encoding genes are highly expressed at the transcript level: Blo t 1, Blo t 5, Blo t 21 (known), Blo t 15, and Blo t 18 (predicted). However, at the protein level, a different set of most abundant allergens was found: Blo t 2, 10, 11, 20 and 21 (mite bodies) or Blo t 3, 4, 6 and predicted Blo t 13, 14 and 36 (mite feces). We report the use of an integrated omics method to identify and predict an array of mite allergens and advanced, label-free proteomics to determine allergen protein abundance. Our research identifies a large set of novel putative allergens and shows that the expression levels of allergen-encoding genes may not be strictly correlated with the actual allergenic protein abundance in mite bodies.

Bacteriocarriage of ixodid mites on the Trans-Baikal Territory

The results of a microbiological study of sexually mature ixodid mites of the genus Dermacentor collected in the rural areas of the Trans-Baikal Territory are presented. Microbiological examination of 152 ixodid mites was carried out. Four microbial cultures of different species were identified: Listeria monocytogenes, E. coli, Salmonella typhi, Clostridium botulinum. The presence of bacteria associations of different species groups in the mite body was noted: in 32 individuals - L. monocytogenes, E. coli, S. typhi, in 56 - C. botulinum, E. coli, S. typhi, in 6 - L. monocytogenes, E. coli, in 15 - C. botulinum, E. coli. Of all the isolated microbial strains, Escherichia coli made up the largest number: this microorganism was isolated from all mites. L. monocytogenes appeared to be the least isolated: 38 of 152 mites were its carriers. Salmonellosis pathogen circulation was detected in 123 mites out of 152 examined specimens. The biological properties of all the isolated microbial cultures corresponded to their classical characteristics. Microorganisms of the genus Clostridium isolated from the mites on the Kitt-Tarozzi nutrient medium caused uniform turbidity of the nutrient medium, which indicates that this bacterial strain belongs to serovars C, D, E and В. The data obtained indicate the need for annual veterinary control of the grazing areas for the presence of natural foci, the reservoirs of pathogens which are pasture mites. During the period of ixodid mites mass attack it is necessary to carry out acaricide treatments of animals with repellent and acaricide preparations that will not only increase their productivity, but will also allow preventing infectious diseases.

Dermoscopy of Crusted Scabies: Revisiting the New and Old Signs.

Dear Editor, Scabies is a common ectoparasitosis in India caused by the eight-legged mite, Sarcoptes scabiei var. hominis. Crusted scabies occurs predominantly in immunosuppressed individuals and presents with diffuse hyperkeratotic scales, crusts, or even erythroderma. It is highly contagious because crusted scabies patient may harbor millions of mites on their body in contrast to 10–12 mites found in classical scabies.[1] It may often be misdiagnosed due to the absence of typical nocturnal pruritus and atypical clinical presentations. Dermoscopy is extremely useful in the diagnosis of this uncommon variant of the common parasitosis. We present a case of crusted scabies showing the classical and newly described dermoscopic signs. A 38-year-old female, case of mixed connective tissue disease, on treatment with daily prednisolone (10 mg) along with azathioprine 100 mg and admitted to the medical ward due to cirrhosis and ascites, presented with skin rash of 1 month duration. On clinical examination, generalized erythematous rash with scaly papules and crusting was seen along with multiple dry crusted hyperkeratotic plaques (showing wet sand appearance) predominantly over the bony prominences, trunk, limbs, and scalp [Figure 1].Figure 1: (a) multiple dry crusted hyperkeratotic plaques with erythematous scaly papules and crusting. (b) scaly crusted plaque involving the scalp. (c) “wet sandpaper” appearance of crusted plaquesDermoscopic examination showed numerous burrows in a “noodle-like pattern” with multiple brownish triangular structures (delta glider sign) [Figure 2a]. These burrows showed the “gray-edged line sign”, which is a gray-brownish line on the outer edges of the burrow (Figure 2b) and wake sign [Figure 3]. Potassium hydroxide (KOH) mount of scales revealed numerous scabies mites and eggs [Figure 4]. On histopathology, hyperkeratosis, parakeratosis, acanthosis, and scabies mites in the stratum corneum were seen [Figure 5]. The patient was advised topical application of 5% permethrin cream every third day for 2 weeks along with oral ivermectin 12 mg to be taken on day 1, 2, and 8.Figure 2: Dermoscopy showing (a) “noodle-like pattern” consisting of accumulation of several curvilinear burrows displaying the “gray-edged line sign” [blue arrowhead (in fig b also)]. (Heine delta NC1, polarized, 10×) (b) brown-colored triangular structure (yellow arrow) that simulates a delta glider trailed by the jet contrail (inset). (Dinolite Videodermoscope polarized non-contact 50x)Figure 3: Wake sign—the burrow (black lines) and the wake-shaped scale (dashed line) together presenting a Y-shaped lesion. (Higher magnification Dinolite Videodermoscope polarized non-contact 50×)Figure 4: Potassium hydroxide mount showing numerous mites (red arrows), eggs (blue arrowhead), and scybala (yellow circles)Figure 5: Multiple scabies mites (black arrow) in stratum corneum (H & E 10x)Burrows are the pathognomonic lesions of scabies; however, they are difficult to be seen on naked eyes, especially in brown skin and in patients with excoriations. Various eponymous dermoscopic signs of scabies include “Delta sign”/“hang glider sign”/“triangle sign” (brownish triangular structures in the shape of hang glider) corresponding to the head and anterior legs of the mite and “Jetliner with contrail sign” (where the mite body appears translucent and air-filled burrow resembles a jetliner with contrail).[2] “Noodle pattern” or “millipede-like structure” (showing numerous burrows) as seen in our case is a characteristic dermoscopy sign of crusted scabies.[3] “Gray-edged line sign” on dermoscopy is a recently described sign where the dark line is often seen on the outer wall of the curved burrow and is supposed to form mainly due to the melanin containing fecal material of the mite, which gets deposited on the outer wall by the tail end of the mite as it crosses the curved burrow.[4] “Wake sign” is described as a pattern of scale reminiscent of the “wake” left on the water surface by a moving object.[5] All the dermoscopic signs were seen in our case. Thus dermoscopy is an extremely useful, rapid, and noninvasive in vivo tool for the diagnosis of crusted scabies. This case is interesting as the dermoscopic signs of noodle pattern and gray-edged line sign have not been previously described in Indian patients. Declaration of patients consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

High-throughput behavioral phenotyping of tiny arthropods: Chemosensory traits in a mesostigmatic hematophagous mite.

Pest management using attractive and/or repellent semiochemicals is a key alternative to synthetic insecticides. Its implementation requires a good understanding of the intra- and interspecific chemical interactions of arthropod pests, their interactions with their abiotic environment, as well as their evolutionary dynamics. Althoughmites include many pest species and biocontrol agents of economic importance in agriculture, their chemical ecology is largely understudied compared to insects. We developed a high-throughput ethomics system to analyze these small arthropods and conducted a study on Dermanyssus gallinae, a problematic poultry parasite in the egg industry. Our purpose was to elucidate the role played by host-derived odorants (synthetic kairomone) and conspecific odorants (mite body odors) in D. gallinae. After validating our nanocomputer controlled olfactometric system with volatile semiochemicals of known biological activity, we characterized response traits to kairomonal and/or pheromonal volatile blends in mites from different populations. We were able to accurately characterize the repulsion or attraction behaviors in >1000 individual specimens in a standardized way. Our results confirm the presence of a volatile aggregation pheromone emitted by D. gallinae and bring new elements to the effect of odor source presentation. Our results also confirm the attractive effect on Dermanyssus gallinae of a blend of volatile compounds contained in hen odor, while highlighting a repellent effect at high concentration. Significant interindividual and interpopulation variation was noted particularly in responses to synthetic kairomone. This information lays a valuable foundation for further exploring the emergence risk of resistance to semiochemicals.

Localized efficacy of environmental RNAi in Tetranychus urticae

Environmental RNAi has been developed as a tool for reverse genetics studies and is an emerging pest control strategy. The ability of environmental RNAi to efficiently down-regulate the expression of endogenous gene targets assumes efficient uptake of dsRNA and its processing. In addition, its efficiency can be augmented by the systemic spread of RNAi signals. Environmental RNAi is now a well-established tool for the manipulation of gene expression in the chelicerate acari, including the two-spotted spider mite, Tetranychus urticae. Here, we focused on eight single and ubiquitously-expressed genes encoding proteins with essential cellular functions. Application of dsRNAs that specifically target these genes led to whole mite body phenotypes—dark or spotless. These phenotypes were associated with a significant reduction of target gene expression, ranging from 20 to 50%, when assessed at the whole mite level. Histological analysis of mites treated with orally-delivered dsRNAs was used to investigate the spatial range of the effectiveness of environmental RNAi. Although macroscopic changes led to two groups of body phenotypes, silencing of target genes was associated with the distinct cellular phenotypes. We show that regardless of the target gene tested, cells that displayed histological changes were those that are in direct contact with the dsRNA-containing gut lumen, suggesting that the greatest efficiency of the orally-delivered dsRNAs is localized to gut tissues in T. urticae.

The Effect of Residual Pesticide Application on Microbiomes of the Storage Mite Tyrophagus putrescentiae.

Arthropods can host well-developed microbial communities, and such microbes can degrade pesticides and confer tolerance to most types of pests. Two cultures of the stored-product mite Tyrophagus putrescentiae, one with a symbiotic microbiome containing Wolbachia and the other without Wolbachia, were compared on pesticide residue (organophosphate: pirimiphos-methyl and pyrethroid: deltamethrin, deltamethrin + piperonyl butoxide)-containing diets. The microbiomes from mite bodies, mite feces and debris from the spent mite diet were analyzed using barcode sequencing. Pesticide tolerance was different among mite cultures and organophosphate and pyrethroid pesticides. The pesticide residues influenced the microbiome composition in both cultures but without any remarkable trend for mite cultures with and without Wolbachia. The most influenced bacterial taxa were Bartonella-like and Bacillus for both cultures and Wolbachia for the culture containing this symbiont. However, there was no direct evidence of any effect of Wolbachia on pesticide tolerance. The high pesticide concentration residues in diets reduced Wolbachia, Bartonella-like and Bacillus in mites of the symbiotic culture. This effect was low for Bartonella-like and Bacillus in the asymbiotic microbiome culture. The results showed that the microbiomes of mites are affected by pesticide residues in the diets, but the effect is not systemic. No actual detoxification effect by the microbiome was observed for the tested pesticides.

Response to González-Pérez et al

We earlier found that house dust mite (HDM) allergens, which occur mainly in mite bodies but not in feces (e.g., Der p 10, Der p 11, and Der p 14), are more frequently recognized by HDM allergic patients with atopic dermatitis (AD) than HDM allergic patients suffering from respiratory allergy (Banerjee et al., 2015). The fact that certain types of the mite body‒derived allergens such as Der p 11 do not become easily airborne and are recognized by >50% of patients with AD suggested that this allergen may be considered a major allergen in AD and that sensitization may eventually occur through the skin (Banerjee et al., 2015).

Spatial distribution pattern of soil mite community and body size in wheat- maize rotation farmland

Spatial distribution pattern of soil mite community and body size in wheat- maize rotation farmland

Antagonism of Protease Activated Receptor-2 by GB88 Reduces Inflammation Triggered by Protease Allergen Tyr-p3

The occurrence of allergic diseases induced by aeroallergens has increased in the past decades. Among inhalant allergens, mites remain the important causal agent of allergic diseases. Storage mites- Tyrophagus putrescentiae are found in stored products or domestic environments. Major allergen Tyr-p3 plays a significant role in triggering IgE-mediated hypersensitivity. However, its effects on pulmonary inflammation, internalization, and activation in human epithelium remain elusive. Protease-activated receptors (PARs) are activated upon cleavage by proteases. A549 cells were used as an epithelial model to examine the PAR activation by Tyr-p3 and therapeutic potential of PAR-2 antagonist (GB88) in allergic responses. Enzymatic properties and allergen localization of Tyr-p3 were performed. The release of inflammatory mediators, phosphorylation of mitogen-activated protein kinase (MAPK), and cell junction disruptions were evaluated after Tyr-p3 challenge. Enzymatic properties determined by substrate digestion and protease inhibitors indicated that Tyr-p3 processes a trypsin-like serine protease activity. The PAR-2 mRNA levels were significantly increased by nTyr-p3 but inhibited by protease inhibitors or GB88. Protease allergen of nTyr-p3 significantly increased the levels of pro-inflammatory cytokines (IL-6 and TNF-α), chemokine (IL-8), and IL-1β in epithelial cells. nTyr-p3 markedly increased phosphorylation of extracellular signal-regulated kinase (ERK)1/2 and MAP kinase. When cells were pretreated with GB88 then added nTyr-p3, the phosphorylated ERK1/2 did not inhibit by GB88. GB88 increased ERK1/2 phosphorylation in human epithelium cells. GB88 is able to block PAR-2-mediated calcium signaling which inhibits the nTyr-p3-induced Ca2+ release. Among the pharmacologic inhibitors, the most effective inhibitor of the nTyr-p3 in the induction of IL-8 or IL-1β levels was GB88 followed by SBTI, MAPK/ERK, ERK, and p38 inhibitors. Levels of inflammatory mediators, including GM-CSF, VEGF, COX-2, TSLP, and IL-33 were reduced by treatment of GB88 or SBTI. Further, GB88 treatment down-regulated the nTyr-p3-induced PAR-2 expression in allergic patients with asthma or rhinitis. Tight junction and adherens junction were disrupted in epithelial cells by nTyr-p3 exposure; however, this effect was avoided by GB88. Immunostaining with frozen sections of the mite body showed the presence of Tyr-p3 throughout the intestinal digestive system, especially in the hindgut around the excretion site. In conclusion, our findings suggest that Tyr-p3 from domestic mites leads to disruption of the airway epithelial barrier after inhalation. Proteolytic activity of Tyr-p3 causes the PAR-2 mRNA expression, thus leading to the release of numerous inflammatory mediators. Antagonism of PAR2 activity suggests GB88 as the therapeutic potential for anti-inflammation medicine, especially in allergy development triggered by protease allergens.

Microbial Communities of Stored Product Mites: Variation by Species and Population.

Arthropod-associated microorganisms are important because they affect host fitness, protect hosts from pathogens, and influence the host's ability to vector pathogens. Stored product mites (Astigmata) often establish large populations in various types of food items, damaging the food by direct feeding and introducing contaminants, including their own bodies, allergen-containing feces, and associated microorganisms. Here we access the microbial structure and abundance in rearing diets, eggs, feces fraction, and mite bodies of 16 mite populations belonging to three species (Carpoglyphus lactis, Acarus siro, and Tyrophagus putrescentiae) using quantitative PCR and 16S ribosomal RNA (rRNA) gene amplicon sequencing. The mite microbiomes had a complex structure dominated by the following bacterial taxa (OTUs): (a) intracellular symbionts of the genera Cardinium and Wolbachia in the mite bodies and eggs; (b) putative gut symbionts of the genera Solitalea, Bartonella, and Sodalis abundant in mite bodies and also present in mite feces; (c) feces-associated or environmental bacteria of the genera Bacillus, Staphylococcus, and Kocuria in the diet, mite bodies, and feces. Interestingly and counterintuitively, the differences between microbial communities in various conspecific mite populations were higher than those between different mite species. To explain some of these differences, we hypothesize that the intracellular bacterial symbionts can affect microbiome composition in mite bodies, causing differences between microbial profiles. Microbial profiles differed between various sample types, such as mite eggs, bodies, and the environment (spent growth medium-SPGM). Low bacterial abundances in eggs may result in stochastic effects in parent-offspring microbial transmission, except for the intracellular symbionts. Bacteria in the rearing diet had little effect on the microbial community structure in SPGM and mite bodies. Mite fitness was positively correlated with bacterial abundance in SPGM and negatively correlated with bacterial abundances in mite bodies. Our study demonstrates critical host-microbe interactions, affecting all stages of mite growth and leading to alteration of the environmental microbiome. Correlational evidence based on absolute quantitation of bacterial 16S rRNA gene copies suggests that mite-associated microorganisms are critical for modulating important pest properties of mites by altering population growth.

Proteogenomics of the house dust mite, Dermatophagoides farinae: Allergen repertoire, accurate allergen identification, isoforms, and sex-biased proteome differences

The allergen repertoire of the house dust mite, Dermatophagoides farinae, is incomplete despite most mite allergens having been described in this species. Using proteogenomics, we aimed to compare proteins and allergens between sexes and provide a foundation for the identification of novel allergens. Overall, 6297 protein hits were identified, and 2899 and 886 were male- and female-specific, respectively. Removal of trace results narrowed the dataset to 3478 hits, including 275 and 157 male- and female-specific hits, respectively. All 34 WHO/IUIS-approved D. farinae allergens (omitting Der f 17) were identified, and we also identified homologs of the yet undescribed Der f 9 and 38. Der f 27/serpin exhibited the largest sex-dependent difference and was dominant in females. Using official protein sequences, Der f 11, 14, 23, 28 and 30 were identified with low success. However, identification success of Der f 11 and 14 was greatly increased by using longer/complete sequences. Der f 30 is characterized by the same tryptic digests as the more abundant Der f 30 (isoform) identified here. Der f 23 appears to be of low abundance in mite bodies. Der f 28.0101 and Der f 28.0201 were detected at low abundance and in trace amounts, respectively. SignificanceIn this work, we performed a proteogenomic annotation of the house dust mite, Dermatophagoides farinae, which is the most important source of house dust allergens. The proteogenomic analysis performed here provides a foundation for not only understanding the biology of the mite but also the identification of novel allergens. This study generated a robust proteomic dataset for D. farinae and reviewed existing and candidate allergens in this species. We stress some pitfalls of high-throughput analyses, especially that improper headers of allergen protein records provided in databases can lead to confusion. Using partial sequences in proteomic identification and quantification can lead to low identification success (low signal intensity or MS/MS counts). Thus, we individually curated the protein sequences for proper identification and quantification. The discovered sex differences can be one factor affecting allergen/immunogen variations in mite extracts. Overall, this work provides a benchmark for accurate identification of mite immunogenic proteins using proteomics.

Mite load predicts the quality of sexual color and locomotor performance in a sexually dichromatic lizard.

Since Darwin, the maintenance of bright sexual colors has recurrently been linked to mate preference. However, the mechanisms underpinning such preferences for bright colors would not be resolved for another century. Likely, the idea of selection for colors that could decrease the chances of survival (e.g., flashy colors that can inadvertently attract predators) was perceived as counterintuitive. It is now widely accepted that these extreme colors often communicate to mates the ability to survive despite a “handicap” and act as honest signals of individual quality when they are correlated with the quality of other traits that are directly linked to individual fitness. Sexual colors in males are frequently perceived as indicators of infection resistance, in particular. Still, there remains considerable discord among studies attempting to parse the relationships between the variables associating sexual color and infection resistance, such as habitat type and body size. This discord may arise from complex interactions between these variables. Here, we ask if sexual color in male Florida scrub lizards (Sceloporus woodi) is an honest signal of resistance to chigger mite infection. To this end, we use linear modeling to explore relationships between mite load, different components of sexual color, ecological performance, body size, and habitat type. Our data show that that the brightness of sexual color in scrub lizards is negatively associated with the interaction between mite load and body size, and scrub lizards suffer decreased endurance capacity with increases in mite load. Our data also indicate that mite load, performance, and sexual color in male scrub lizards can vary between habitat types. Collectively, these results suggest that sexual color in scrub lizards is an honest indicator of individual quality and further underscore the importance of considering multiple factors when testing hypotheses related to the maintenance of sexual color.

Characterisation of three novel β-1,3 glucanases from the medically important house dust mite Dermatophagoides pteronyssinus (airmid)

The European house dust mite, Dermatophagoides pteronyssinus is a major source of airborne allergens worldwide and is found in half of European homes. Interactions between microbes and house dust mites (HDM) are considered important factors that allow them to persist in the home. Laboratory studies indicate the European HDM, D. pteronyssinus is a mycophagous mite, capable of utilising a variety of fungi for nutrients, however specific mycolytic digestive enzymes are unknown. Our previous work identified a number of putative glycosyl hydrolases present in the predicted proteome of D. pteronyssinus airmid and validated the expression of 42 of these. Of note, three GH16 proteins with predicted β-1,3 glucanase activity were found to be consistently present in the mite body and excretome. Here, we performed an extensive bioinformatic, proteomic and biochemical study to characterize three-novel β-1,3 glucanases from this medically important house dust mite. The genes encoding novel β-1,3 glucanases designated Glu1, Glu2 and Glu3 were identified in D. pteronyssinus airmid, each exhibited more than 59% amino acid identity to one another. These enzymes are encoded by Glu genes present in a tri-gene cluster and protein homologs are found in other acari. The patchy phyletic distribution of Glu proteins means their evolutionary history remains elusive, however horizontal gene transfer cannot be completely excluded. Recombinant Glu1 and Glu2 exhibit hydrolytic activity toward laminarin, pachyman and barley glucan. Excreted β-1,3 glucanase activity was increased in response to D. pteronyssinus airmid feeding on baker's yeast. Active β-1,3 glucanases are expressed and excreted in the faeces of D. pteronyssinus airmid indicating they are digestive enzymes capable of breaking down β-1,3 glucans of fungi present in house dust.

Computational investigation of dust mite allergens in a realistic human nasal cavity

Aim: Inhaled allergens from house dust mite (HDM) are a major source of allergic disease such as allergic rhinitis and asthma. It has been a challenge to properly evaluate health risks caused by HDM related allergens including mite bodies, eggs and fecal pellets. This paper presents a numerical study on particle deposition of dust mite allergens in a human nasal cavity.Materials and methods: A realistic nasal cavity model was reconstructed from CT scans and a Computational Fluid Dynamics analysis of steady airflow was simulated. The discrete phase model was used to trace particle trajectories of three dust mite related particles.Results: The flow and particle model were validated by comparing with nasal resistance measurement and previous literature respectively. Aerodynamic characteristics and deposition of dust mite allergens in the nasal cavity were analyzed under different breathing conditions including rest and exercising conditions.Conclusions: The numerical results revealed the roles of different nasal cavity regions in filtering various types of dust mite allergens with consideration of breathing conditions.

Proteome and allergenome of the European house dust mite Dermatophagoides pteronyssinus.

The European house dust mite Dermatophagoides pteronyssinus is of significant medical importance as it is a major elicitor of allergic illnesses. In this analysis we have undertaken comprehensive bioinformatic and proteomic examination of Dermatophagoides pteronyssinus airmid, identified 12,530 predicted proteins and validated the expression of 4,002 proteins. Examination of homology between predicted proteins and allergens from other species revealed as much as 2.6% of the D. pteronyssinus airmid proteins may cause an allergenic response. Many of the potential allergens have evidence for expression (n = 259) and excretion (n = 161) making them interesting targets for future allergen studies. Comparative proteomic analysis of mite body and spent growth medium facilitated qualitative assessment of mite group allergen localisation. Protein extracts from house dust contain a substantial number of uncharacterised D. pteronyssinus proteins in addition to known and putative allergens. Novel D. pteronyssinus proteins were identified to be highly abundant both in house dust and laboratory cultures and included numerous carbohydrate active enzymes that may be involved in cuticle remodelling, bacteriophagy or mycophagy. These data may have clinical applications in the development of allergen-specific immunotherapy that mimic natural exposure. Using a phylogenomic approach utilising a supermatrix and supertree methodologies we also show that D. pteronyssinus is more closely related to Euroglyphus maynei than Dermatophagoides farinae.

Ultrastructure and functional morphology of dermal glands in the freshwater mite Limnochares aquatica (L., 1758) (Acariformes, Limnocharidae)

This study is the first attempt to describe the ultrastructure and functional morphology of the dermal glands in Limnochares aquatica (L., 1758). The dermal glands were studied using light-optical, SEM and TEM microscopy methods during different stages of their activity. In contrast to the vast majority of other fresh water mites, dermal glands of the studied species are originally multiplied and scattered freely over the mite body surface. The opening of the glands is saddle-like, formed of several tight cuticular folds and oriented freely to the long axis of the mite body. Either a small cuticular spine or, rarely, a slim sensitive seta is placed on one pole of the opening. On the inside, the central gland portion is provided with a complex cuticular helicoid armature. The glands are composed of prismatic cells situated around the intra-alveolar lumen, variously present, and look like a fig-fruit with the basal surface facing the body cavity. The glands are provided with extremely numerous microtubules, frequently arranged in bundles, and totally devoid of synthetic apparatus such as RER cisterns and Golgi bodies. Three states of the gland morphology depending on their functional activity may be recognized: (i) glands without secretion with highly folded cell walls and numerous microtubules within the cytoplasm, (ii) glands with an electron-dense granular secretion in the expanded vacuoles and (iii) glands with the secretion totally extruded presenting giant empty vacuoles bordered with slim cytoplasmic strips on the periphery. Summer specimens usually show the first gland state, whereas winter specimens, conversely, more often demonstrate the second and the third states. This situation may depend on some factors like changes of the seasonal temperature, pH, or oxygenation of the ambient water. On the assumption of the morphological characters, dermal glands may be classified not as secretory but as a special additional excretory organ system of the body cavity. Despite the glands lack cambial cells, restoration of functions after releasing of ‘secretion’ looks possible. Organization of dermal glands is discussed in comparison to other water mites studied.