Tyrophagus Putrescentiae Research Articles

The Negative Effects of Feces-Associated Microorganisms on the Fitness of the Stored Product Mite Tyrophagus putrescentiae.

Feces have been suggested as a major source of microorganisms for recolonization of the gut of stored product mites via coprophagy. The mites can host microorganisms that decrease their fitness, but their transmission is not known. To address the role of fecal microbiota on mite fitness, we performed an experimental study in which the surfaces of mite (Tyrophagus putrescentiae) eggs were sterilized. Mites eggs (15 per experimental box) were then hatched and grown on feedstock with and without feces. These experiments were conducted with four distinct T. putrescentiae populations (5L, 5K, 5N, and 5P), and mite population density after 21 day of cultivation was used to assess mite fitness and the impact of fecal microbiota on fitness. Population density was not affected by the presence of feces in two of the cultures (5L and 5K), while significant effects of feces were observed in the other cultures (5N and 5P). Mite culture microbial communities were analyzed using cultivation-independent next-generation amplicon sequencing of microbial 16S and 18S ribosomal RNA (rRNA) genes in the fitness influenced populations (5N and 5P). Several microbial taxa were associated with fecal treatments and reduced mite fitness, including Staphylococcus and Bartonella-like bacteria, and the fungal genera Yamadazyma, Candida, and Aspergillus. Although coprophagy is the transmission route mites used to obtain beneficial gut bacteria such as Bartonella-like organisms, the results of this study demonstrate that fecal-associated microorganisms can have negative effects on some populations of T. putrescentiae fitness, and this may counteract the positive effects of gut symbiont acquisition.

Influence of laying hen-systems and ecologic variables on mites of medical and veterinary importance

The search for improvements in the poultry production chain and for increased egg productivity have grown significantly. However, intensive production with or by using of confinement systems negatively affect the welfare of animals and is favoring the appearance of harmful ectoparasites in production. Due to differences in the existing management systems, (e.g. Californian and cage-free systems) and given the importance of the poultry industry in the international market, the aim of the present study was: (1) to compare mite community between SIG (Intensive system – cage: Californian) and SIF (Intensive system – free: cage free); (2) egg-laying systems to analyze how the abundances of the ectoparasites Dermanyssus gallinae, Megninia ginlgymura, and Ornithonyssus sylviarum are affected by these egg-laying models; (3) to evaluate the association between the functional diversity found in traps, organic matter, and feathers in both systems; and finally, (4) to analyze how abiotic factors (e.g. humidity, temperature at sampling) affect mite community composition inside each model. A total of 860,571 mites were sampled, belonging to 59 taxa from six functional groups. Mite composition in the SIF system was different from the SIG system, while their variations in dispersion homogeneity were quite similar to each other. Although taxonomic composition is different between them, they are quite similar when clustered according to functional diversity. The variables 'humidity' and 'temperature' were not determining factors for the appearance of species. The species that most contributed for distinguishing the models were: M. ginlgymura, Dermatophagoides farinae, D. gallinae, Tyrophagus putrescentiae, O. sylviarum, Blattisocius keegani, Glycyphagus sp., Acotyledon sp., and Cheyletus malaccensis, respectively. Dermanyssus gallinae was strongly associated with the Californian model. Two taxa were highly correlated with cloaca, neck, dorsum, and inner wings; variations in relative air humidity also affected M. ginlgymura and O. sylviarum populations. Organic matter had a high abundance of predatory mites with potential for controlling mites of sanitary importance in the poultry chain.

Cost-effective and efficient factitious prey for mass production of Neoseiulus cucumeris (Acari: Phytoseiidae): assessing its quality compared with natural prey

BackgroundUsing alternative diets for the mass production of phytoseiid predatory mites may facilitate their cost-effective rearing. Factitious prey is often used as an alternative food source for mass rearing of generalist phytoseiids. The generalist predator, Neoseiulus cucumeris (Oudemans), is a commercially available biocontrol agent against various pests. We assessed the suitability of two factitious prey, Ephestia kuehniella Zeller eggs and Tyrophagus putrescentiae (Schrank), as diets for long-term rearing (up to 30 generations) of N. cucumeris, when compared with a natural prey, Tetranychus urticae Koch.ResultsThe predator completed its development on all tested diets successfully. Under laboratory conditions, Tyrophagus putrescentiae could support the development and oviposition of the predator for up to 30 generations even better than its natural prey T. urticae. However, the eggs of E. kuehniella were not suitable for this predator because of the longer pre-adult period and adults failed to reproduce.ConclusionsSince rearing on T. putrescentiae for a long time had no adverse effects on the predator’s performance, this factitious prey could be considered as a suitable and cost-effective diet for mass production of N. cucumeris.

Nitric Oxide Fumigation for Control of Ham Mite, Tyrophagus putrescentiae (Sarcoptiformes: Acaridae).

The ham mite, Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae), is a common pest infesting several stored products, particularly the aged hams. In this study, we reported the efficacy of nitric oxide (NO) fumigation, a recently discovered fumigation treatment under the ultra-low oxygen environment, at various concentrations and time under the laboratory conditions at 25°C against different mite stages on both dietary media and ham meat. Our results showed that NO fumigation was effective against all mite stages and 100% control was achieved. Generally, the egg was the most tolerant stage and required 48-, 24-, 16-, and 8-h treatments to achieve 100% mortality at 0.5, 1, 1.5, and 2% NO concentration on dietary media, respectively. Tyrophagus putrescentiae mobile immatures and adult stages were less tolerant, and 100% mortality was achieved after 16-, 8-, 8-, and 4-h treatment at 0.5, 1, 1.5, and 2% NO, respectively. The median lethal concentration (LC50) of NO on egg was 0.86, 0.68, and 0.32% for 8-, 16-, and 24-h treatments. In addition, a confirmatory test was conducted on ham meat at 0.5 and 1.0% of NO and similar efficacy was found. Complete control of egg was achieved after 48- and 24-h treatment at 0.5 and 1.0% of NO, respectively, and larvae and adult mites were 100% controlled after 16 and 8 h at 0.5 and 1.0% of NO, respectively. Our results demonstrated that NO fumigation was effective against T. putrescentiae and can be a potential alternative treatment to methyl bromide for cured-ham pest control.

Effects of Local Nasal Immunotherapy with FIP-fve Peptide and Denatured Tyrophagus putrescentiae for Storage Mite-Induced Airway Inflammation.

Allergic diseases are affecting public health and have increased over the last decade. Sensitization to mite allergens is a considerable trigger for allergy development. Storage mite-Tyrophagus putrescentiae shows great significance of allergenic potential and clinical relevance. The fungal immunomodulatory peptide FIP-fve has been reported to possess immunomodulatory activity. We aimed to determine whether T. putrescentiae-induced sensitization and airway inflammation in mice could be downregulated by FIP-fve in conjunction with denatured T. putrescentiae (FIP-fve and DN-Tp). Immune responses and physiologic variations in immunoglobulins, leukocyte subpopulations, cytokine productions, pulmonary function, lung pathology, cytokines in CD4+ and Treg cells were evaluated after local nasal immunotherapy (LNIT). After the LNIT with FIP-fve and DN-Tp, levels of specific IgE, IgG1, and IgG2a in the sera and IgA in the bronchoalveolar lavage fluid (BALF) were significantly reduced. Infiltrations of inflammatory leukocytes (eosinophils, neutrophils, and lymphocytes) in the airway decreased significantly. Production of proinflammatory cytokines (IL-5, IL-13, IL-17F and IL-23) and chemokine (IL-8) were significantly reduced, and Th1-cytokine (IL-12) increased in the airway BALF after LNIT. Pulmonary functions of Penh values were significantly decreased after the methacholine challenge, which resulted in a reduction of airway hypersensitivity after LNIT. Bronchus pathology showed a reduction of inflammatory cell infiltration and epithelium damage after LNIT. The IL-4+/CD4+ T cells could be downregulated and the IFN-γ+/CD4+ T cells upregulated. The Treg-related immunity of IL-10 and Foxp3 expressions in CD4+CD25+ cells were both upregulated after LNIT. In conclusion, LNIT with FIP-fve and DN-Tp had an anti-inflammatory effect on mite-induced airway inflammations and possesses potential as an immunomodulatory therapy agent for allergic airway diseases.

First report of Tyrophagus putrescentiae (Schrank) (Acari: Acaridae) in colonies of the stingless bee Frieseomelitta varia (Hymenoptera, Apidae, Meliponini)

Tyrophagus putrescentiae (Schrank) (Acari: Acaridae) has the potential for controlling pest insects in the laboratory, although little is known about its interaction with beneficial species such as bees. Here we report an infestation of T. putrescentiae and its predatory effect in colonies of the stingless bee Frieseomelitta varia (Hymenoptera, Apidae, Meliponini) in Minas Gerais State, Brazil. After the mite infestation, the F. varia colonies became weak and the population died. Because T. putrescentiae develops preferentially in warm and damp environments, special care should be taken when performing in vitro rearing (e.g., sterilizing transfer needles, tweezers, and incubators) of F. varia. Moreover, stingless bee colonies maintained in meliponaries should be periodically monitored, in order to prevent not only mite infestation but diverse health issues.

Massive infestation of Tyrophagus putrescentiae (Astigmata: Acaridae) inside an office in City of Panama, Panama

We report the presence of unusual overpopulation of the storage mite Tyrophagus putrescentiae in an office workplace, an environment that often does not provide the ideal conditions for the development of these mites. The infestation source was identified as two damaged sachets of spoiled sweetener found under the furniture of the office used for preparing and consuming refreshments.

Comparison of biological characteristics of the predatory mite Blattisocius mali (Acari: Blattisocidae) reared on frozen eggs of Tyrophagus putrescentiae (Acari: Acaridae) alone and in combination with cattail and olive pollens

Blattisocius mali (Oudemans), known as a predator of some species of storage pest mites, was reared on frozen eggs of Tyrophagus putrescentiae (Schrank) alone (Tp) but also supplemented with cattail (Tp + cattail) and olive (Tp + olive) pollen. Life table parameters of B. mali were evaluated in the first (G1), eighth (G8) and sixteenth (G16) generation on the three different diets. Survival of the immatures of the predator was not affected by the tested diets, whereas it significantly differed among generations. The highest and lowest mortality was observed in the G8 and G1 generations, respectively, on all diets. Except for the total pre-oviposition period (TPOP) and the adult pre-oviposition period (APOP), all life table parameters of B. mali were affected by the different diets; In G1, supplementation of (Tp) with both pollens significantly increased the fecundity, oviposition period and female life span of B. mali. Population growth parameters of the predator like intrinsic rate of increase (r), net reproductive rate (R0) and finite rate of increase (λ) significantly increased with the supplementation of (Tp) with cattail pollen. However, in G8 and G16, B. mali reared on the two combinations significantly showed the lowest values of oviposition period, female and male life span and mean generation time (T) (only F8). Except for female and male developmental times and TPOP, other biological parameters of B. mali significantly differ across generations. Adding both pollens to the frozen eggs of the prey mite, significantly decreased fecundity, oviposition period, female and male life span and population parameters such as (r), (T), (λ) of B. mali in G16 compared with G1. With comparison of the effects of diet through the generations on biological and population parameters of B. mali, it is concluded that frozen eggs of T. putrescentiae is strongly advisable for mass-rearing of the predator and mixed frozen diets (containing pollen) is suggested as supplemental diet for establishment of the predator after release.

Biological parameters and host preference of Tyrophagus putrescentiae (Schrank) on different Pleurotus ostreatus cultivars

Tyrophagus putrescentiae (Acari: Acaridae) is a destructive pest of edible fungi. Different species of edible fungi have variable effects on the growth, development and fecundity of T. putrescentiae, but it is unclear whether these effects exist in the same species. We used nine cultivars of the oyster mushroom (Pleurotus ostreatus) to evaluate the development and reproduction parameters of T. putrescentiae at 26 ± 1°C and 80 ± 5% humidity. Different P. ostreatus cultivars had significant effects on the immature stages, female fertility, and reproductive lifespan. Total egg-to-adult development time ranged from 10.0 ± 1.2 d (on Po389 cultivar) to 12.5 ± 1.0 d (on Po62 cultivar). Mite mortality ranged from 54.3 ± 4.2% (on Po86 cultivar) to 100.0 ± 0.0% (on Po62 cultivar). The number of eggs laid per female ranged from 3.2 ± 0.4 (on Po45 cultivar) to 9.1 ± 1.1 (on Po86 cultivar). The average lifespan of females ranged from 3.0 ± 0.5 d (on Po45 cultivar) to 16.3 ± 1.7 d (on Po86 cultivar). Host preference of the mite was significantly different among the nine cultivars with a preference for cultivars Po65, Po80, Po389, and Po86. These results indicate that P. ostreatus cultivars significantly affect the biology of T. putrescentiae and the relationship between mite damage and mushroom yield.

Allergic sensitization to storage dust mites: a prospective study of patients with respiratory allergy

Objectives. To describe the prevalence of allergic sensitization to Storage Dust Mites (SDM), access whether the place of living and occupational exposure were determinants for SDM sensitization and study association between Lepidoglyphus destructor and other SDM sensitization. Methods. Prospective analysis of patients evaluated for suspected allergic rhinitis and/or asthma that performed Skin Prick Tests (SPT) to SDM between January and December 2018 in our Department. Results. Two hundred consecutive patients were evaluated for rhinitis and/or asthma in our outpatient consultation: 123 (61.5%) presented positivity for at least one SDM, 68.3% were female and the mean age was 33.1 ± 12.12. Lepidoglyphus destructor (69.9%) was the most prevalent, followed by Tyrophagus putrescentiae (50.4%), Blomia tropicalis and Glycyphagus domesticus (48.8%) and Acarus siro (24.4%). Living in a rural place was not associated with a higher prevalence of sensitization to SDM, except for Acarus siro (p = 0.032), and working in a place with storage areas was not associated with sensitization to any of SDM. Sensitization to Lepidoglyphus destructor was associated with sensitization to Blomia tropicalis, Glycyphagus domesticus and Tyrophagus putrescentiae (p less than 0.005), but not with Acarus siro. Conclusions. Our study suggests that our population, independently of their occupational exposure and place of residency, are sensitized to SDM and that evaluation of sensitization to SDM should be considered as standard practice.

A rapid identification method for common astigmatid species based on multiplex polymerase chain reaction.

Astigmatid mites are economically significant pests of stored products and sources of inhalant allergens causing allergic rhinitis and asthma worldwide. The morphological identification of astigmatid mites at the species level is often a difficult task due to their small size, phenotypic similarity and lack of diagnostic characters. We used multiplex polymerase chain reaction (PCR) to identify astigmatid mite species, which could complement the morphological data for the species-specific identification of mites. Internal ribosomal transcribed spacer (ITS) sequences (i.e., partial 18S, the full length of ITS1-5.8S-ITS2 and partial 28S) from eight astigmatid species (Acarus siro, Tyrophagus putrescentiae, Suidasia nesbitti, Dermatophagoides pteronyssinus, Dermatophagoides farinae, Lepidoglyphus destructor, Chortoglyphus arcuatus and Gohieria fuscus) were obtained by DNA extraction and then sequenced after PCR amplification. Specific primers were designed in the ITS2 region manually. Results revealed that an identification method for eight common astigmatid species was established based on multiplex PCR, which should be effective for the identification of other species of mites by redesigning species-specific primers in future experiments.

Acaricidal properties of 5-methylfurfural identified from Valeriana fauriei and its structural analogues against synanthropic mites and Asian longhorned tick with color alterations

Acaricidal activities and color alterations of 5-methylfurfural derived from Valeriana fauriei essential oil and its structural analogues against Dermatophagoides farinae, D. pteronyssinus, Haemaphysalis longicornis and Tyrophagus putrescentiae were evaluated in the present study. Based on the LD50 values of 5-methylfurfural and its analogues, 4,5-dimethylfurfural showed the highest acaricidal activity (LD50; 9.95, 9.91, and 7.12 μg/cm2), followed by 5-methylfurfural (11.87, 11.00, and 8.59 μg/cm2), furfural (12.94, 13.25, and 10.36 μg/cm2), and V. fauriei essential oil (15.15, 13.64, and 10.14 μg/cm2) against D. farinae, D. pteronyssinus and T. putrescentiae, respectively. However, all tested compounds did not show the acaricidal activities against H. longicornis. Interestingly, the color alterations of the mites and ticks were observed by furfural, 5-methylfurfural, and 4,5-dimethylfurfural from colorless to red brown during the acaricidal experiments. Furthermore, 4,5-dimethylfurfural which exhibited the highest acaricidal activity was formulated as nanoemulsion. The nanoemulsion of 4,5-dimethylfurfural showed higher acaricidal activity than it was emulsified in ethanol. The nanoemulsion was also found to show color changes of the mites and ticks from colorless to red brown. The results suggest that 5-methylfurfural and its analogues could be developed as an effective and easy-to-recognize acaricides to mites and ticks.

Active and frozen host mite Tyrophagus putrescentiae (Acari: Acaridae) influence the mass production of the predatory mite Blattisocius mali (Acari: Blattisociidae): life table analysis

Blattisocius mali (Oudemans) is a candidate predatory mite on some astigmatid mite pests like Tyrophagus putrescentiae (Schrank). In current study, life table parameters of B. mali were comparatively evaluated when fed on mixed life stages, frozen (one day at -20°C) and cold stored (90 days at -20°C and 4°C) eggs of T. putrescentiae. The highest and lowest values of fecundity, total longevity, oviposition period, life span and adult longevity of B. mali were observed when the predator provided with one-day and 90-days frozen eggs (stored at 4°C) of T. putrescentiae, respectively. Moreover, the highest values of net reproductive rate (R0), intrinsic rate of increase (r) and finite rate of increase (λ) of B. mali were obtained by feeding on one-day frozen eggs (23.94 offspring/individual, 0.332 day-1, 1.39 day-1, respectively), without significant differences from the predators reared on alive mixed stages of T. putrescentiae. However, the lowest values of R0 (1.54 offspring/individual), r (0.058 day-1) and λ (1.06 day-1) were recorded when B. mali was reared on 90-days frozen eggs (stored at 4°C). The results, as first evidence of life-history of B. mali, represent not only the potential of the predator as suitable biological control agent against T. putrescentiae, but also the possibility of its mass production by frozen host stages. Provision of one-day frozen eggs of T. putrescentiae were the best choice for B. mali survival and reproduction with no harmful effects of living stages (direct damage, frass and exuviae) on crop.

The application of chitosan in food-grade coatings to control Tyrophagus putrescentiae on dry-cured hams and the effects on sensory properties

The objective of this research was to evaluate if chitosan-containing food-grade coatings can control Tyrophagus putrescentiae growth without affecting the sensory attributes of dry-cured hams. Food-grade coating treatments included (1) 0.3% chitosan (CH), (2) 0.6% CH, (3) 0.3% CH + 10% propylene glycol (PG), (4) 0.3% CH + 1% xanthan gum (XG), (5) 0.3% CH + 1% XG + 10% PG, (6) 0.3% CH + 1% carrageenan (CG) + 1% propylene glycol alginate (PGA), and (7) 0.3% CH + 1% CG + 1% PGA + 10% PG. Each coating solution was coated on ham cubes (2.54 × 2.54 × 2.54 cm3, n = 5/treatment) or infused in ham nets and dry-cured ham cubes were wrapped in the ham nets prior to inoculation with 20 adult mites. A randomized complete block design with three replications was utilized to evaluate the efficacy of treatments at controlling mite growth on dry-cured ham. When CH was mixed with XG (0.3% CH + 10% PG + 1% XG, and 0.3% CH + 1% XG) and infused into a net, fewer mites (15.7 and 21.0 mites) were on the ham cubes (P < 0.05) in comparison to the control (211.2 mites). Results indicate that CH has the efficacy to control mites since 1% XG alone did not control mite growth. Difference from control test results indicated that no sensory differences existed (NS) between CH-treated and control ham slices. The addition of chitosan coated nets helped control mite growth when used in conjunction with xanthan gum and propylene glycol and collectively may be useable as part of an integrated pest management plan for ham producers to control mites in their aging houses. Therefore, these coating solutions could be scaled up to evaluate their efficacy in ham aging houses.

Pollen Feeding Reduces Predation of Northern Corn Rootworm Eggs (Coleoptera: Chrysomelidae, Diabrotica barberi) by a Soil-Dwelling Mite (Acari: Laelapidae: Stratiolaelapsscimitus).

Simple SummaryFlowering plants are used to enhance pest control by predators and parasitoids, but insect herbivores can also use floral resources. We documented the species of adult rootworm beetles on key plants, and found that northern corn rootworm (NCR) adults were commonly associated with sunflower inflorescences while western corn rootworm adults were most abundant in corn and on squash blossoms. Consumption of sunflower and corn pollen by NCR adults did not impact predation of their eggs by an omnivorous mite, but a predatory soil-dwelling mite ate pest eggs less frequently and took longer to feed on eggs when NCR adults had fed on sunflower pollen. While increasing plant diversity can benefit natural enemies and pest control within agroecosystems, it is important to consider how floral resources alter dietary preferences of biocontrol agents.Landscape diversification with flowering plants can benefit pollinators and natural enemies, although insect pests can also use floral resources for nutrition and chemoprotection. Corn rootworms (Coleoptera: Chrysomelidae, Diabrotica spp.) are major pests of corn (Zea mays L.), and while subterranean larvae primarily feed on corn roots, adult rootworms commonly consume floral resources from other plant species. We quantified the species, density, and sex of adult corn Diabroticite rootworm beetles on wild and cultivated sunflower, corn, and squash, quantified pollen within the bodies of adult northern corn rootworms [NCR, D. barberi (Smith & Lawrence)], and investigated how consumption of sunflower and corn pollen by NCR adults impacted predation of their eggs by two soil-dwelling mites with different feeding specialization. NCR were the most common Diabroticite species on sunflower inflorescences and western corn rootworm (WCR, D. v. virgifera LeConte) were more abundant in corn and squash blossoms. Pollen feeding by NCR adults did not impact egg predation by omnivorous Tyrophagus putrescentiae (Schrank) (Acari: Sarcoptiformes, Acaridae), but predatory Stratiolaelaps scimitus (Womersley) (Acari: Mesostigmata, Laelapidae) ate eggs less frequently and took longer to feed on eggs from NCR females that had fed on sunflower pollen. This research suggests pollen feeding by adult NCR can impact predation of their eggs. While increasing plant diversity can benefit natural enemies and pest control within agroecosystems, it is important to consider how floral resources alter dietary preferences of biocontrol agents.

First record and verification of Tyrophagus putrescentiae (Acari: Acaridae) causing direct damage on anthurium plants cultivated in vitro

The population size at which Tyrophagus putrescentiae can produce damage on anthurium plants (Anthurium sp.), cultivated in vitro, was determined. Symptoms caused by these mites on the plants are described. Two anthurium varieties coded as ANMIRO and ANWHGE, were cultivated in a Murashige and Skoog medium for four weeks. The treatments for each variety were as follows: a) Absolute Control (AC), b) fungus inoculated in the cultured medium (CF), c) fungus on leaves + mites (FLM), d) fungus in medium + mites (FMM), and e) only mites (OM). Mite density within the vessels increased through time. Fifty-five days after the first evaluation, the highest amount of injury was observed in the treatments FLM, FMM, and OM. The observed symptoms were holes on the foliar lamina produced by the feeding of mites until complete plant deterioration. According to the prediction model, when there is an average population close to 62 mites per vessel, it would be expected to find 20% damaged. The probability of observing damage on the variety ANWHGE was 1.7 times higher than on the variety ANMIRO. Although T. putrescentiae is a known contaminant in tissue culture laboratories as it carries bacteria and fungi on its body, this is the first record of this species causing direct damage to plants cultivated in vitro.

Regulatory roles of three miRNAs on allergen mRNA expression in Tyrophagus putrescentiae

Tyrophagus putresecentiae is an important mite species in rural and urban environments, causing sensitization and allergic disease. While evidence suggests that microRNAs (miRNAs) may regulate the expression of allergen-encoding genes, no study has directly investigated this possibility. Here, this gap was addressed by profiling miRNAs and elucidating their target allergen messenger RNAs (mRNAs) in this mite species. Small RNA and transcriptome libraries were constructed for eggs, larvae, nymphs, and adults. After deep miRNA and whole-transcriptome sequencing were performed, the miRNA and allergen-encoding mRNA regulatory networks were explored. A total of 540miRNAs were identified, including 155 with expression levels differing significantly across the four mite developmental stages (p<.01), 59 of which were novel. The mRNA expression for allergens was higher for Tyr p 1 in adults than in other developmental stages; Tyr p 2-5, 7, 10, 13, 33, and 34 in immature stages; and Tyr p 28, 35, and 36 in eggs and adults. A combined miRNA and transcriptome bioinformatics analysis showed that allergen Tyr p 3 was regulated by miRNA PC-5p-5698441_1, Tyr p 4 was regulated by PC-5p-7050653_1, and Tyr p 34 was regulated by PC-5p-5534223_1 and PC-5p-5698441_1. These three allergen mRNA and three miRNAs were identified using qRT-PCR, and their regulatory roles were confirmed by double-fluorescent reporter gene system and site-directed mutagenesis technology. For the first time, allergen mRNA expression and miRNAs were profiled throughout the life cycle for an allergen-producing mite, and the results showed that miRNAs bind to target allergen mRNAs to regulate their expression.

Effects of infestations of the storage mite Tyrophagus putrescentiae (Acaridae) on the presence of fungal species and mycotoxin production in stored products

The storage mite Tyrophagus putrescentiae (Schrank) (Acari: Acaridae) is one of the most important pests of stored foods (cheese, corn, oats, wheat, soy etc.), and is found in heavy infestations. Mites can infest food that are stored under unsatisfactory sanitary conditions, which may also provide conditions for fungi growth, which indicates mite-fungus association. However, little is known about the influence of T. putrescentiae on mycotoxins production under different stored products over time. The main objective of the present study was to identify the fungal species present in oats, corn, and wheat flour associated with T. putrescentiae infestations, and evaluate mycotoxin production before and after six months storage with these infestations. Wheat, corn and oat grain samples were compared, and each crop was stored in six containers infested by T. putrescentiae. Three remaining containers were stored under the same temperature and humidity conditions without introducing the mites, which worked as control. We obtained 55 fungi isolates, and the majority were identified with 99% or 100% of identity and ≥97% of coverage with type strains of each fungal species. Mycotoxin concentrations analyzed from corn flour stored for six months decreased with and without T. putrescentiae (p < 0.05). Regarding mycotoxin concentration with T. putrescentiae, aflatoxin increased in oats (p < 0.05) while zearalenone decreased in wheat (p < 0.05). Our findings proved that T. putrescentiae could significantly induce mycotoxin production in stored products evaluated for six months.

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.

Cardinium inhibits Wolbachia in its mite host, Tyrophagus putrescentiae, and affects host fitness.

Interactions among endosymbiotic bacteria inside their eukaryotic hosts are poorly understood, particularly in mites. The mite Tyrophagus putrescentiae is a common, medically important generalist species that has many intracellular and gut bacterial symbionts. In the experiments, we examined bacterial abundances and composition in mite populations obtained by controlled mixing of stock mite populations that differed in the presence/absence of the major intracellular bacteria Wolbachia and Cardinium. Changes in microbial communities were characterized using 16S ribosomal RNA high-throughput sequencing (pooled mite individuals) and quantitative PCR for key microbial taxa (individual mites). Mite fitness was estimated as a parameter of population growth. We detected that in mixed mite populations, Cardinium and Wolbachia can co-occur in the same mite individual. The presence of Cardinium was negatively correlated with the presence of Wolbachia and Bartonella, while the Bartonella and Wolbachia were positively correlated in individual level samples. Since mixed populations had lower abundances of Wolbachia, while the abundance of Cardinium did not change, we suggest that the presence of Cardinium inhibits the growth of Wolbachia. The mixed mite populations had lower population growth than parental populations. The possible effect of symbionts on the fitness of mixed population is discussed.