Integrated Transcriptome and Metabolome Dynamic Analysis of Galls Induced by the Gall Mite Aceria pallida on Lycium barbarum Reveals the Molecular Mechanism Underlying Gall Formation and Development.

Galls have become the best model for exploring plant-gall inducer relationships, with most studies focusing on gall-inducing insects but few on gall mites. The gall mite Aceria pallida is a major pest of wolfberry, usually inducing galls on its leaves. For a better understanding of gall mite growth and development, the dynamics of the morphological and molecular characteristics and phytohormones of galls induced by A. pallida were studied by histological observation, transcriptomics and metabolomics. The galls developed from cell elongation of the epidermis and cell hyperplasia of mesophylls. The galls grew quickly, within 9 days, and the mite population increased rapidly within 18 days. The genes involved in chlorophyll biosynthesis, photosynthesis and phytohormone synthesis were significantly downregulated in galled tissues, but the genes associated with mitochondrial energy metabolism, transmembrane transport, carbohydrates and amino acid synthesis were distinctly upregulated. The levels of carbohydrates, amino acids and their derivatives, and indole-3-acetic acid (IAA) and cytokinins (CKs), were markedly enhanced in galled tissues. Interestingly, much higher contents of IAA and CKs were detected in gall mites than in plant tissues. These results suggest that galls act as nutrient sinks and favor increased accumulation of nutrients for mites, and that gall mites may contribute IAA and CKs during gall formation.

Effects of in-house and commercial extracts of the allergenic mite Tyrophagus putrescentiae on murine and human cell responses.

Mites are among the major sources of domestic and occupational allergens worldwide, and continuous exposure to these allergens leads to chronic airway inflammation. One of the most allergenic species is the storage mite Tyrophagus putrescentiae (Schrank). Protein extracts are produced from this mite for tests that help the clinical diagnosis (via prick test), treatment, and monitoring of disease progression in patients who had positive results for allergic reactions. Therefore, the aim of the present study was to evaluate the cell viability of RAW 264.7 and L929 cells when exposed to in-house raw protein extracts of T. putrescentiae compared to a commercial product, as well as quantify TNF-α secretion by RAW 264.7. Additionally, this study quantified the effect of these extracts in IgE secretion in total blood of people affected by this mite. The study found similarity between the in-house extract and the commercial extract as they had equivalent TNF-α secretion. Additionally, viabilities of RAW 264.7 and L929 exposed to the in-house extract were compatible with viabilities of cells exposed to the commercial extract, with no cytotoxicity at the concentrations tested. Results corroborated the hypothesis that the extract produced in-house would be equivalent to the commercial extract in allergic patients when the IgE was quantified. This study is the first to show the cytotoxicity of T. putrescentiae extracts, and to provide a quantitative analysis of TNF-α and IgE.

Plant insects and mites uptake double-stranded RNA upon its exogenous application on tomato leaves.

MAIN CONCLUSION: Exogenously applied double-stranded RNA (dsRNA) molecules onto tomato leaves, moved rapidly from local to systemic leaves and were uptaken by agricultural pests namely aphids, whiteflies and mites. Four small interfering RNAs, deriving from the applied dsRNA, were molecularly detected in plants, aphids and mites but not in whiteflies. Double-stranded RNA (dsRNA) acts as the elicitor molecule of the RNA silencing (RNA interference, RNAi), the endogenous and evolutionary conserved surveillance system present in all eukaryotes. DsRNAs and their subsequent degradation products, namely the small interfering RNAs (siRNAs), act in a sequence-specific manner to control gene expression. Exogenous application of dsRNAs onto plants elicits resistance against plant viruses. In the present work, exogenously applied dsRNA molecules, derived from Zucchini yellow mosaic virus (ZYMV) HC-Pro region, onto tomato plants were detected in aphids (Myzus persicae), whiteflies (Trialeurodes vaporariorum) and mites (Tetranychus urticae) that were fed on treated as well as systemic tomato leaves. Furthermore, four siRNAs, deriving from the dsRNA applied, were detected in tomato and the agricultural pests fed on treated tomato plants. More specifically, dsRNA was detected in agricultural pests at 3 and 10 dpt (days post treatment) in dsRNA-treated leaves and at 14 dpt in systemic leaves. In addition, using stem-loop RT-PCR, siRNAs were detected in agricultural pests at 3 and 10 dpt in aphids and mites. Surprisingly, in whiteflies carrying the applied dsRNA, siRNAs were not molecularly detected. Our results showed that, upon exogenous application of dsRNAs molecules, these moved rapidly within tomato and were uptaken by agricultural pests fed on treated tomato. As a result, this non-transgenic method has the potential to control important crop pests via RNA silencing of vital genes of the respective pests.

Toxicokinetics and time-variable toxicity of cadmium in Oppia nitens Koch (Acari: Oribatida).

The soil-living mite Oppia nitens Koch has recently been proposed as a promising test species for the ecotoxicological risk assessment of contaminated boreal soils. Adding oribatid mites to the assemblage of test species for soil is highly desirable given the enormous diversity and ecological significance of these microarthropods. The authors aimed at revealing how toxicity, lethal body concentration, and bioaccumulation of cadmium (Cd) changed over a period of 7 wk when mites were exposed to Cd-spiked natural soils. The estimated median lethal concentration (LC50) values showed a gradual decrease with time, but a steady state was not reached within 7 wk. Estimates for lethal body concentration varied from 44 µg Cd/g to 91 µg Cd/g dry body weight, with a tendency to increase with time. The estimated 50% effective concentration (EC50) for effects on reproduction after 7-wk exposure was 345 µg Cd/g dry soil. Accumulation of Cd in mites was extremely variable but overall showed a nonsaturating increase. A simple 1-compartment toxicokinetic model did not describe the data well. The analysis suggests that O. nitens has a storage-detoxification strategy that is not at equilibrium under chronic exposure. Considering the tiny body size of the animal, it is remarkable that long exposure times are necessary to reveal chronic toxicity. The use of oribatids provides a clear added value to soil risk assessment but trades off with exposure length. Environ Toxicol Chem 2017;36:408-413. © 2016 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

GM-CSF-licensed CD11b+ lung dendritic cells orchestrate Th2 immunity to Blomia tropicalis.

The Blomia tropicalis dust mite is prevalent in tropical and subtropical regions of the world. Although it is a leading cause of asthma, little is known how it induces allergy. Using a novel murine asthma model induced by intranasal exposure to B. tropicalis, we observed that a single intranasal sensitization to B. tropicalis extract induces strong Th2 priming in the lung draining lymph node. Resident CD11b(+) dendritic cells (DCs) preferentially transport Ag from the lung to the draining lymph node and are crucial for the initiation of Th2 CD4(+) T cell responses. As a consequence, mice selectively deficient in CD11b(+) DCs exhibited attenuated Th2 responses and more importantly did not develop any allergic inflammation. Conversely, mice deficient in CD103(+) DCs and CCR2-dependent monocyte-derived DCs exhibited similar allergic inflammation compared with their wild-type counterparts. We also show that CD11b(+) DCs constitutively express higher levels of GM-CSF receptor compared with CD103(+) DCs and are thus selectively licensed by lung epithelial-derived GM-CSF to induce Th2 immunity. Taken together, our study identifies GM-CSF-licensed CD11b(+) lung DCs as a key component for induction of Th2 responses and represents a potential target for therapeutic intervention in allergy.

Paternal effects on the expression of a male polyphenism.

Polyphenic traits are widespread, but compared to other traits, relatively few studies have explored the mechanisms that influence their inheritance. Here we investigated the relative importance of additive, nonadditive genetic, and parental sources of variation in the expression of polyphenic male dimorphism in the mite Rhizoglyphus echinopus, a species in which males are either fighters or scramblers. We established eight inbred lines through eight generations of full-sibling matings, and then crossed the inbred lines in a partial diallel design. Nymphs were isolated and raised to adulthood with ad libitum food. At adulthood, male morph was recorded for all male offspring. Using a Cockerham-Weir model, we found strong paternal effects for this polyphenic trait that could be either linked to the Y chromosome of males or an indirect genetic effect that is environmentally transmitted. In additional analyses, we were able to corroborate the paternal effects but also detected significant additive effects questioning the Cockerham-Weir analysis. This study reveals the potential importance of paternal effects on the expression of polyphenic traits and sheds light on the complex genetic architecture of these traits.

Regeneration of complex oil-gland secretions and its importance for chemical defense in an oribatid mite.

Most oribatid mites possess a pair of opisthonotal exocrine glands that produce mostly complex, species-specific secretions. Such blends may contain more than 10 different compounds, but hardly anything is known about their primary biosynthesis or regeneration. I analyzed recovery of the 6 main components from the 11-compound secretion of the oribatid mite Archegozetes longisetosus Aoki, including the main chemical classes hydrocarbons, aromatics, and terpenes, during a 20-day time course after complete gland depletion. About 10 % of the original total secretion amount was restored after 24 hr, and after 2-6 days, the amount had reached the range of total amount observed in the control group. Most compounds were recovered at similar rates within the first 48 hr. An important exception was pentadecane, which was predominantly produced in the first few hours, suggesting that this compound is the main solvent of the secretion. Although relative amounts of the main compounds differed significantly over time, the complex profile of the whole secretion was stable and not confidently distinguishable among the sampling dates. The general recovery rate was high during the first 48 hr, about 25 times higher than in the remaining 18 days. The biological importance of this high initial investment was supported by predation experiments: the predacious rove beetle Stenus juno was first repelled after 48 hr when at least 25 % of secretions was restored.

Tasty but protected--first evidence of chemical defense in oribatid mites.

Oribatid mites (Acari, Oribatida) represent one of the most abundant and speciose groups of microarthropods in the decomposer food webs of soils, but little is known of their top-down regulation by predators. Oribatids are relatively long-lived and have numerous morphological defensive adaptations, and so have been proposed to live in 'enemy-free space'. Most also possess a pair of large exocrine oil glands that produce species-specific mixtures of hydrocarbons, terpenes, aromatics, and alkaloids with presumably allomonal functions, although their adaptive value has never been tested empirically. We developed a protocol that discharges the oil glands of the model oribatid species, Archegozetes longisetosus. and offered 'disarmed' individuals as prey to polyphagous Stenus beetles (Staphylinidae), using untreated mites as controls. Stenus juno fed on disarmed mites with behavioral sequences and success rates similar to those observed when they prey on springtails, a common prey. In contrast, mites from the control group with full glands were almost completely rejected; contact with the gland region elicited a strong reaction and cleaning behavior in the beetle. This is the first evidence of an adaptive value of oribatid mite oil gland secretions for chemical defense. The protocol of discharging oil glands should facilitate future studies on top-down control of oribatid mites that aim to differentiate between morphological and chemical aspects of defensive strategies.

Anafilaxia oral por alimentos contaminados por ácaros: (síndrome de las panquecas) / Oral anaphylaxis by mite contaminated food: (the pancake syndrome)

La anafilaxia oral por ácaros es un nuevo síndrome caracterizado por síntomas alérgicos graves que se presentan en individuos alérgicos rápidamente después de la ingestion de alimentos confeccionados con harinas de trigo contaminadas con ácaros. Este síndrome más común en ambientes tropicales, es desencadenado más frecuentemente por panquecas y por ello ha sido designado "el síndrome de las panquecas". Se postula que los alergenos responsables son alergenos termorresistentes ya que los alimentos cocinados son capaces de inducir los síntomas. Una variedad del síndrome puede presentarse durante el ejercicio físico (anafilaxia inducida por ejercicio asociada a la ingestión de polvo con ácaros). Se recomienda conservar las harinas de trigo en el refrigerador para prevenir la proliferación de los ácaros y la aparición del cuadro clínico.

Oral mite anaphylaxis is a new syndrome characterized by severe allergic symptoms occurring in allergic patients immediately after the intake of foods made with mite-contaminated wheat flour. This syndrome, which is more common in tropical environments, is triggered more aften by pancakes and for that reason it has been designated "the pancake syndrome". Since cooked foods are able to induce the symptoms, it has been suggested that thermoresistant allergens are involved. A variety of this syndrome can occur during physical exercise (dust mite-ingestion associated exercise induced anaphylaxis). In order to prevent mite proliferation and the production of the clinical picture it is recommended to store wheat flours in the refrigerator.

Localisation of heavy metals in the midgut epithelial cells of Xenillus tegeocranus (Hermann, 1804) (Acari: Oribatida).

Sites of intracellular metal deposition in the midgut ventriculus and in the proventricular glands of Xenillus tegeocranus (Hermann, 1804) (Acari: Oribatida) were studied by TEM. The study aimed to obtain new information on the ultrastructural features of heavy metal compartmentalisation and elimination mechanisms in oribatid mites. Specimens of X. tegeocranus were collected from an abandoned mining and smelting area and from an unpolluted site. A large number of electron-dense granules (EDGs) were detected: concentric spherocrystals were observed mainly in the epithelium of the midgut ventriculus, while homogeneous dark granules were found exclusively in proventricular gland cells. The elemental composition of EDGs, studied by X-ray microanalysis, showed that midgut cells of X. tegeocranus can store metals (Fe, Mn, Zn, Ni, and Cu) in granules. The chemical composition of EDGs seems to be influenced by the presence and bioavailability of heavy metals in soil, with different kinds of metals accumulating in different types of granules.

Deposition of IgD, alpha-1-antitrypsin and alpha-1-antichymotrypsin on Demodex folliculorum and D. brevis infesting the pilosebaceous unit.

A total of seven routinely processed biopsy specimens of facial skin lesions with infestation of Demodex folliculorum or D. brevis were immunostained for plasma proteins and secretory proteins. The cuticular layer of the mites located within the pilosebaceous unit was selectively immunoreactive for IgD (delta chain), alpha-1-antitrypsin and alpha-1-antichymotrypsin. Negative results were obtained for IgG, IgA, IgM, IgE, albumin, fibrinogen, C3, amyloid P component, prealbumin, lysozyme and lactoferrin. These findings suggest a novel function of IgD and serum protease inhibitors as a protective host response to the mite.

Chemical ecology of oribatid mites III. Chemical composition of oil gland exudates from two oribatid mites, Trhypochthoniellus sp. and Trhypochthonius japonicus (Acari: Trhypochthoniidae).

The composition of oil gland exudates from two oribatid mites, Trhypochthoniellus sp. and Trhypochthonius japonicus, was studied with reference to the related species Trhypochthoniellus crassus. Trhypochthoniellus sp. contained a mixture of seven compounds; (Z,Z)-6,9-heptadecadiene, geranial, 3-hydroxybenzene-1,2-dicarbaldehyde (gamma-acaridial), neryl formate, neral, (Z)-8-heptadecene and geranyl formate in decreasing order of abundance. The profile of the components from T. japonicus consisted of two types depending on the locality of sampling with unknown reason; one possessing a mixture of eight compounds [(Z,E)-farnesal, gamma-acaridial, (Z,Z)-6,9-heptadecadiene, (E,E)-farnesal, (Z)-8-heptadecene and geranial in decreasing order] together with two unknown compounds, and the other composed of the same set of compounds together with 2-hydroxy-6-methylbenzaldehyde as the most abundant component. Relative abundance among common components was consistent between the two types of T. japonicus. Profiles of components differed among three species including T. crasus. The phylogenetic relationship between Oribatida and Astigmata was discussed based on secretory compounds commonly distributed between these two suborders.

Chemistry of the oil gland secretion of Collohmannia gigantea (Acari: Oribatida).

The chemistry of the lemon-scented oil gland secretion of Collohmannia gigantea, a middle-derivative mixonomatan oribatid mite, was investigated by gas chromatography - mass spectrometry. Gas chromatographic profiles of whole body extracts of C. gigantea revealed two distinct chromatographic zones, the first containing a set of six volatile compounds, comprising the lemon-scented monoterpene aldehydes neral and geranial, the scented monoterpene ester neryl formate, a distinctly scented aromatic aldehyde (2-hydroxy-6-methyl-benzaldehyde = 2,6-HMBD), and the two non-scented hydrocarbons, tridecane and pentadecane. All six components appeared to be present in steady relative proportions in scenting mites only, indicating their unity within the scented secretion. In contrast, the components of the second chromatographic zone were less volatile and found in both, scenting and nonscenting mites. Chemically, they represent a set of fatty acids of already known cuticular origin. The secretion bouquet of the first chromatographic zone was linked with oil glands by histochemical means: large amounts of aldehydes were present only in oil gland reservoirs, not in any other region of the mite body. While chemical profiles of oil gland secretions of several dozen astigmatid mites are known, only one other oribatid oil gland composition, from a desmonomatan species, has been elucidated, being almost the same as that of C. gigantea. Moreover, all components of these two secretions are widely distributed amongst astigmatid mite species and may also be common in a restricted set of middle-derivative oribatids. These findings are consistent with the idea of astigmatid mite origin from a mixonomatan-desmonomatan group.

Interaction of human lung surfactant proteins A and D with mite (Dermatophagoides pteronyssinus) allergens.

Human lung surfactant proteins A (SP-A) and D (SP-D) are both collagenous C-type lectins which appear to mediate antimicrobial activity by binding to carbohydrates on micro-organisms and to receptors on phagocytic cells. Purified native SP-A and SP-D, isolated from human bronchoalveolar lavage fluid, were found to bind to whole mite extracts (Dermatophagoides pteronyssinus) and the purified allergen Der p I, in a carbohydrate-specific and calcium-dependent manner. Binding was inhibited by ethylenediamine tetra-acetic acid (EDTA) as well as by maltose in the case of SP-D, or mannose in the case of SP-A. A recombinant polypeptide, which trimerized to form the neck region and carbohydrate recognition domains of SP-D, also inhibited the binding of native SP-D to the whole mite extract and Der p I. Both SP-A and SP-D did not bind to deglycosylated whole mite extracts or to recombinant Der p proteins, which lacked carbohydrate residues. These results suggest that the ability of surfactant proteins to bind certain allergens is mediated through their carbohydrate-recognition domains (CRDs) interacting with carbohydrate residues on the allergens. Moreover, SP-A and SP-D were found to inhibit allergen-specific IgE binding to the mite extracts either via steric hindrance or competitive binding. It is therefore possible that SP-A and SP-D may be involved in the modulation of allergen sensitization and/or the development of allergic reactions.

Identification and characterization of tox21A: a mite cDNA encoding a paralytic neurotoxin related to TxP-I.

A cDNA library established from polyadenylated RNA isolated from the predatory mite Pyemotes tritici was screened for cDNAs homologous to tox34, a cDNA encoding an insect-selective paralytic neurotoxin known as TxP-I. Most of the cDNA inserts of homologous clones were shorter or of equal length to tox34 but a few were longer. Further investigation into the nature of these longer clones led to the identification, sequencing and expression of a distinct cDNA referred to as tox21A. This cDNA is predicted to encode a polypeptide which shares approximately 83% amino acid identity with TxP-I. Larvae infected with a recombinant baculovirus expressing tox21A are paralyzed during infection in a manner similar to larvae infected with tox34-expressing recombinants. The tox21A cDNA may represent a duplicated and diverged copy of the TxP-I gene.

Inhibition of ATP dephosphorylation by acaricides with emphasis on the anti-ATPase activity of the carbodiimide metabolite of diafenthiuron.

3-(2,6-Diisopropyl-4-phenoxyphenyl)-1-tert-butylcarbodiimide (DFCD), a toxic metabolite and photodegradation product of the propesticide diafenthiuron, and dicyclohexylcarbodiimide (DCCD), a commonly used biochemical inhibitory probe, inhibited Mg(2+)-, Na+K(+)-, and Ca2+Mg(2+)-ATPase activities in preparations from bulb mites (Rhizoglyphus echinopus (Fumouze and Robin)), twospotted spider mites (Tetranychus urticae Koch), and bluegill (Lepomis macrochirus Rafinesque) brain. DCCD was more active than DFCD, but neither carbodiimide was very potent. A possible exception occurred with DCCD, which caused 100% inhibition of bulb mite oligomycin-sensitive Mg(2+)-ATPase activity at a concentration of 0.1 mM. Using house fly, Musca domestica L., thorax mitochondrial Mg(2+)-ATPase, we showed that the binding domain for both carbodiimides was in the F0 portion of the enzyme, probably the transmembrane proton channel which is the known site of DCCD binding in proton-translocating ATPases. Certain other specific acaricides were inhibitors (greater than 50% at 0.1 mM) of ATPase preparations from bulb mites. These acaricides included chloropropylate, bromopropylate, oxythioquinox, cyhexatin, and flubenzimine (Mg2+ and Na+K(+)-ATPase), and ovex, chlorbenside, and propargite (Mg(2+)-ATPase). The role of ATPase inhibition in the modes of acaricidal and insecticidal actions of diafenthiuron, the two carbodiimides, and the other compounds is discussed.

Biochemical and physiological effects of chlordimeform.

Chlordimeform is a relatively new acaricide/insecticide, whose mode of action we have investigated. It appears to interfere with amine-mediated control of nervous and endocrine systems in a variety of ways. Specifically, chlordimeform causes a build-up of the amines 5-hydroxytryptamine and to a lesser extent norepinephrine in the rat brain in vivo, antagonizes the in vivo action of reserpine in the rat (reserpine depletes amine stores in the CNS), inhibits monoamine oxidase from rat liver in vitro, and causes hypotension in rabbits. In the American cockroach it directly stimulates the heart in situ, acts synergistically with tryptamine in vivo, inhibits amine-N-acetyltransferase from cockroach head in vitro, causes accumulation of indolamines in cockroaches in vivo, and blocks the stimulation of adenylate cyclase by octopamine in the cockroach CNS in situ. It also inhibits tryptamine metabolism in whole mites in vitro.