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PubMed2006

The proteins encoded by the pogo-like Lemi1 element bind the TIRs and subterminal repeated motifs of the Arabidopsis Emigrant MITE: consequences for the transposition mechanism of MITEs.

MITEs (miniature inverted-repeated transposable elements) are a particular class of defective DNA transposons usually present within genomes as high copy number populations of highly homogeneous elements. Although an active MITE, the mPing element, has recently been characterized in rice, the transposition mechanism of MITEs remains unknown. It has been proposed that transposases of related transposons could mobilize MITEs in trans. Moreover, it has also been proposed that the presence of conserved terminal inverted-repeated (TIR) sequences could be the only requirement of MITEs for mobilization, allowing divergent or unrelated elements to be mobilized by a particular transposase. We present here evidence for a recent mobility of the Arabidopsis Emigrant MITE and we report on the capacity of the proteins encoded by the related Lemi1 transposon, a pogo-related element, to specifically bind Emigrant elements. This suggests that Lemi1 could mobilize Emigrant elements and makes the Lemi1/Emigrant couple an ideal system to study the transposition mechanism of MITEs. Our results show that Lemi1 proteins bind Emigrant TIRs but also bind cooperatively to subterminal repeated motifs. The requirement of internal sequences for the formation of proper DNA/protein structure could affect the capacity of divergent MITEs to be mobilized by distantly related transposases.

Arabidopsis↗

PubMed1991

Susceptibilities of northern fowl mite, Ornithonyssus sylviarum (Acarina: Macronyssidae), and chicken mite, Dermanyssus gallinae (Acarina: Dermanyssidae), to selected acaricides.

The relative toxicities of ten acaricides to northern fowl mite, Ornithonyssus sylviarum (Canestrini and Fanzago), and the chicken mite, Dermanyssus gallinae (De Geer), were determined simultaneously by holding the mites inside disposable glass Pasteur pipettes previously immersed in acetone solutions of various concentrations (w/v) of technical grade acaricides. The LC90s (parts per million) of the acaricides after 24 h exposure for the northern fowl mite and the chicken mite, respectively, were: bendiocarb (13.1, 0.18), tetrachlorvinphos (14.5, 4.07), carbaryl (15.0, 0.83), pirimiphos methyl (18.3, 2.03), permethrin (23.1, 8.46), lambda cyhalothrin (80.7, 11.4), dichlorvos (252.8, 3.75), malathion (238.4, 6.59), amitraz (6741, 9430) and fenvalerate (greater than 10,000, 60.2). After 48 h exposure there were only slight increases in mortalities of both species except for increased mortalities for the northern fowl mite with lambda cyhalothrin, amitraz and fenvalerate, and for the chicken mite with amitraz.

Animals↗

PubMed1987

Comparison by electroblotting of IgE-binding components in extracts of house dust mite bodies and spent mite culture.

Eight Dermatophagoides pteronyssinus extracts (three culture extracts, four mite body extracts, and the World Health Organization International Standard [IS]) were investigated by side-by-side sodium dodecyl sulfate-polyacrylamide gel electrophoresis, by electrotransfer to nitrocellulose, and by probing with a pooled serum from mite-allergic subjects. Representative body and mite culture extracts were compared by probing with individual sera, and both types of extract were also compared by RAST-inhibition studies. Extracts from the same source differed in the molecular weight (MW) of some of their IgE-binding components. In general, most IgE-binding components in culture extracts and the IS were in the 14 to 35 kd MW region, whereas extracts from mite bodies and one culture extract contained more IgE-binding components of higher MW (35 to 110 kd). Comparison of representative mite body and culture extracts by use of 22 separate sera resolved 26 and 19 IgE-binding components in the two extracts, respectively. Patterns of RAST inhibition produced by both types of extracts when they were used either as the inhibitor or as the allergosorbent demonstrated qualitative differences between the two types of extracts. These results demonstrate that mite extracts may differ considerably in their allergenic composition and emphasize the need for standardization of mite allergenic extracts and the reexamination of the suitability of the D. pteronyssinus IS.

Animals↗

PubMed2001

[House dust mites and storage compartment mites as allergy inducers].

Perennial respiratory diseases like chronic rhinopathy or bronchial asthma can often be related to an allergy to indoor allergens. Of these, the most relevant allergens are derived from house dust mites. Epidemiologic data show that 8.9% of the general population exhibit a sensitization to house dust mites. Based on a better knowledge of the biology and the living habits of house dust mites effective allergen avoidance measures can be performed which are, however, quite cumbersome and go beyond just encasing mattresses. Of particular relevance is the reduction of the relative humidity below 50%. Relatives of house dust mites are storage mites which are increasingly realized as an important cause of respiratory allergies. The most important is Lepidoglyphus destructor which is dominant in dust probes from Europe and shows crossreactivity with other storage mites. They are found in barns and grain stores and are thus important causes for occupational respiratory diseases in farmers. The existence of storage mites in house dust is connected with damp housing conditions.

Animals↗

PubMed1996

Transient sensitization to house-dust mites: a study on the influence of mite exposure and sex.

This study aimed to evaluate the prognosis of a previous positive skin test to house-dust mites (HDM) in relation to environmental exposure. A total of 115 children, 50 from Stockholm and 65 from northern Sweden, all with a previous (average 2.5 years) positive Phazet (Pharmacia AB, Uppsala, Sweden) skin prick test (SPT) to extracts of Dermatophagoides pteronyssinus (Dpt) and/or D. farinae (Df) were included. Dust samples were collected from the children's mattresses, and the total (Dpt, Df, and D. microceras [Dm]) amount of major mite allergen was measured by ELISA (50 children) and expressed as microgram allergen per gram of dust, or was measured by microscopy (65 children). The results of microscopic mite counts were transformed to approximate allergen levels as 2 micrograms equals 100 mites per gram of dust. Of 115 originally SPT-positive children, only 48 (48%) remained positive at retest, while the majority (58%) were SPT negative after 2 years. Among the 67 converted children, 11 were still exposed to mite allergen, but only to low concentrations (only one converted child being exposed above the suggested threshold level [TLV] of 2 micrograms/g), compared to 15/48 children still SPT positive who were exposed above the TLV. This shows that continued mite exposure is a major risk factor (OR = 30, CI 4.8-184) for continued positive SPT to HDM. A minor risk factor for continued sensitization was sex, boys having a higher risk than girls (OR = 2.2, CI 1.0-4.8). In conclusion, a surprisingly high rate of SPT conversion occurred, mainly as a result of a favorable indoor environment with low exposure to HDM and, to a lesser degree, as a result of sex. The present results support the view that the risk level of exposure is 2 micrograms mite allergen per gram of dust.

Allergens↗

PubMed2000

[Investigation of the mite fauna content of dust samples collected from pig and poultry farms. Report of the first finding in Western Europe of the house-dust mite Dermatophagoides evansi in dust from poultry houses].

Mites can be important sources of airborne allergens, especially on farms. Two dust samples from pig farms and three dust samples from poultry farms were investigated for mites. House-dust mites were present in the poultry-dust samples, but not in the pig-dust samples. Furthermore, storage mites and predatory mites also were found in the poultry-dust samples. Specifically, the house-dust mite Dermatophagoides evansi was found in the dust samples from two poultry farms. Subsequently, a dust sample was collected from five other poultry farms. Again, D. evansi was present in dust from these farms. This is the first time that D. evansi is reported in dust from poultry farms in Western Europe outside Norway. If D. evansi cross-reacts with other Dermatophagoides spp., then poultry farmers and their families, but also other professionals working in the poultry industry, such as veterinarians, may be exposed to house-dust mites with potential clinical consequences, both domestic and occupational.

Allergens↗

PubMed1990

[Results of patch test using mite components in atopic dermatitis (AD) patients. 1st report. "As is patch test" using crushed mites].

UNLABELLED: As is patch test using crushed live mites and crushed dried dead mites of Dermatophagoides pteronyssinus (D.p.), Dermatophagoides farinae (D.f.), & Tryophagus ptrescentiae (T.p.) was performed on 49 AD patients and 18 control patients suffering from dermatitis other than AD. RESULTS: 1) with crushed dried dead mites all patients showed negative reactions but with live mites 11 among 49 AD patients were positive (22.4%); 2) female mites were more positive than males at the rate 8:1; 3) with cases positive to mites, (a) D.p. was positive in all 11 positive cases (100%), (b) D.f. was negative in 5 cases (0%), and (c) T.p. was positive in 2 cases among 4 (50%); 4) because of the pathological manifestations of spongiosis and the infiltration of histiocytes and lymphocytes, the possibility of contact allergy to mite elements was suggested, as a mechanism of atopic dermatitis.

Adolescent↗

PubMed2005

Effectiveness of the BT mite trap for detecting the storage mite pests, Acarus siro, Lepidoglyphus destructor and Tyrophagus longior.

Traps have been used extensively to provide early warning of hidden pest infestations. To date, however, there is only one type of trap on the market in the U.K. for storage mites, namely the BT mite trap, or monitor. Laboratory studies have shown that under the test conditions (20 degrees C, 65% RH) the BT trap is effective at detecting mites for at least 10 days for all three species tested: Lepidoglyphus destructor, Tyrophagus longior and Acarus siro. Further tests showed that all three species reached a trap at a distance of approximately 80 cm in a 24 h period. In experiments using 100 mites of each species, and regardless of either temperature (15 or 20 degrees C) or relative humidity (65 or 80% RH), the most abundant species in the traps was T. longior, followed by A. siro then L. destructor. Trap catches were highest at 20 degrees C and 65% RH. Temperature had a greater effect on mite numbers than humidity. Tests using different densities of each mite species showed that the number of L. destructor found in/on the trap was significantly reduced when either of the other two species was dominant. It would appear that there is an interaction between L. destructor and the other two mite species which affects relative numbers found within the trap.

Acaridae↗

PubMed2006

Scabies mite inactivated serine protease paralogues are present both internally in the mite gut and externally in feces.

The scabies mite, Sarcoptes scabiei, is the causative agent of scabies, a disease that is common among disadvantaged populations and facilitates streptococcal infections with serious sequelae. Previously, we encountered large families of genes encoding paralogues of house dust mite protease allergens with their catalytic sites inactivated by mutation (scabies mite inactivated protease paralogues [SMIPPs]). We postulated that SMIPPs have evolved as an adaptation to the parasitic lifestyle of the scabies mite, functioning as competitive inhibitors of proteases involved in the host-parasite interaction. To propose testable hypotheses for their functions, it is essential to know their locations in the mite. Here we show by immunohistochemistry that SMIPPs exist in two compartments: 1) internal to the mite in the gut and 2) external to the mite after excretion from the gut in scybala (fecal pellets). SMIPPs may well function in both of these compartments to evade host proteases.

Animals↗

PubMed1989

Allergenic and antigenic relationship between three species of storage mite and the house dust mite, Dermatophagoides pteronyssinus.

We have explored the antigenic and allergenic relationship between the house dust mite Dermatophagoides pteronyssinus and three species of storage mite, Glycyphagus destructor, Acarus siro, and Tyrophagus longior. Crossed immunoelectrophoresis demonstrated that all the mite extracts contained multiple antigens but that there was only limited cross-reactivity between the different species. Six sera were obtained from workers exposed to storage mites and with occupationally related lower respiratory tract symptoms. All workers had specific IgE to D. pteronyssinus and to one or more of the storage mites. The pattern of reactivity varied between the different sera, two responded primarily to D. pteronyssinus and A. siro and four sera to D. pteronyssinus and G. destructor. Only weak responses were observed to T. longior. RAST-inhibition and affinity-absorption experiments demonstrated that D. pteronyssinus had at least three groups of distinct allergenic determinants, determinants specific to D. pteronyssinus, determinants shared with A. siro, and determinants shared with G. destructor. Similarly, both A. siro and G. destructor have specific allergenic determinants and determinants shared with D. pteronyssinus. The findings demonstrate the complexity of the immunologic responses to the different mite species.

Allergens↗

PubMed1991

Airborne dust mite allergens: comparison of group II allergens with group I mite allergen and cat-allergen Fel d I.

The form in which allergens become airborne is important because it may influence both symptoms caused by allergen exposure and methods used to reduce exposure. The group I allergens from dust mites only become airborne during disturbance and fall rapidly, which is in keeping with their being carried on fecal pellets. Their mean size is approximately 20 microns in diameter. By contrast, the cat-allergen Fel d I is airborne on particles varying from greater than 10 to less than 2 microns in diameter, some of which remain airborne even without disturbance. A second group of mite allergens, molecular weight 14,000, are equally important and are associated predominantly with mite bodies. With a monoclonal antibody-based assay and a cascade impactor, we have investigated the form in which group II mite allergens become airborne. The results reveal that these allergens only become airborne during disturbance and that they fall within 15 minutes. However, the mean size of particles carrying group II allergens appears to be slightly smaller than the mean size of particles carrying group I allergens. In addition, the quantities of group II allergen becoming airborne during disturbance (mean, 26 ng/m3) could not be explained by the quantity found in fecal particles. Thus, group II mite allergens become airborne in a form quite distinct from cat allergens and very similar to group I mite allergens; however, it appears unlikely that fecal particles are the main form in which group II allergens become airborne.

Allergens↗

PubMed1999

IgE sensitivity and cross-reactivity to crude and purified mite allergens (Der f 1, Der f 2, Der p 1, Der p 2) in atopic dogs sensitive to Dermatophagoides mite allergens.

The present study investigates IgE-reactivity to crude and purified mite allergens by intradermal skin test (IDST), Immunodot method, and ELISA in atopic dogs sensitive to mite allergens, as well as the allergenic cross-reactivity between Dermatophgoides (D) farinae (DF) and D. pteronyssinus (DP) in dogs by IgE-ELISA inhibition. IDST and Immunodot method for crude mite allergens were performed for atopic dogs and 16 atopic dogs showed sensitivity to mite allergens. Of the 16 dogs, all dogs had anti-DF IgE and 11 had anti-DP IgE. We measured specific IgE to purified major allergens (Der f 1, Der f 2, Der p 1, Der p 2). Of the 16 atopic dogs, six had anti-Der f 1 IgE and seven had anti-Der f 2 IgE. Similarly, of the 16 dogs, six had anti-Der p 1 IgE and seven had anti-Der p 2 IgE. However, eight dogs had no specific IgE to these mite allergens. These dogs may be sensitive to other major mite allergens except Der 1 and Der 2. In the dogs that had both anti-DF and DP IgE, IgE binding to DF was greatly inhibited by DP, and reciprocal inhibition was observed. Based on these data, it appears that there is a strong cross-reactivity between DF and DP in dogs. Similarly, a cross-reactivity between DF and DP in purified allergens was also observed. IDST and Immunodot method are useful methods for the diagnosis of atopic diseases in dogs, and ELISA is a useful method for further investigation of IgE-reactivity for the allergens.

Allergens↗

PubMed1991

Cross-antigenicity between the scabies mite, Sarcoptes scabiei, and the house dust mite, Dermatophagoides pteronyssinus.

This study demonstrated that antigens of the parasitic mite Sarcoptes scabiei (SS) cross-react with antigens of the house dust mite Dermatophagoides pteronyssinus (DP). Crossed immunoelectrophoresis (CIE) reaction of SS extract with rabbit anti-DP serum resulted in multiple immunoprecipitates. Reciprocal CIE reactions gave similar results. Immunoprecipitates from both reactions bound IgE in the sera of dust-mite-sensitive patients who had no history of scabies. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis resolved protein/peptide bands of both SS and DP also bound serum IgE from dust-mite-allergic patients following immunoblotting. Non-allergic control sera gave no IgE binding to either SS or DP antigens. These results indicate that patients with atopy to dust mites exhibit circulating antibodies built to DP but that recognize determinants on SS antigens. It is highly probable that scabietic patients build antibodies to SS antigens that also recognize DP antigens. These results raise questions concerning the reported isotypic antibody responses to SS because the sensitivity of scabietic patients to house dust mites has not been previously evaluated. This cross-reactivity may play an important role in the susceptibility to scabies and its clinical manifestations.

Allergens↗

PubMed1989

A controlled trial of house dust mite eradication using natamycin in homes of patients with atopic dermatitis: effect on clinical status and mite populations.

In a controlled clinical trial, patients with atopic dermatitis carried out house dust mite eradication procedures on their mattresses, using natamycin or a matched placebo spray, with or without vacuum cleaning, for 4 months. For the two groups that used vacuum cleaning, mite numbers fell significantly both by comparison of mean initial and final numbers and by calculating mean rates of reduction from regression analyses (P less than 0.01 in all cases). There were no differences between the groups in the magnitude of the decreases. For the two groups that did not use vacuum cleaning, mite populations remained virtually unchanged. These results indicate vacuum cleaning not natamycin had the major effect on mite eradication. Mean symptom scores of patients in all four groups were slightly reduced by the end of the trial, but there was a greater reduction rate (P less than 0.01) in the combined scores of the groups that did not use vacuum cleaning, demonstrating a lack of correlation between improvement in clinical score and lowered mite numbers. No patients entered remission and the maximum improvement in clinical score was only 47%. Natamycin and vacuum cleaning neither alone nor in combination proved valuable in reducing mite numbers sufficiently to provide clinical benefit.

Adolescent↗

PubMed1989

Reduction of house dust mites and mite allergens: effects of spraying carpets and blankets with Allersearch DMS, an acaricide combined with an allergen reducing agent.

Two studies were made to determine the acaricidal and allergen reducing properties of Allersearch DMS solution. In Study 1, samples of dust and carpet containing living mites were treated, in vitro, with DMS solution. No living mites were found in dust after 3-4 min or in carpets 50 min after treatment. In Study 2, mite counts and allergen estimation made on bed blankets before and after spraying with DMS solution showed a marked reduction in mite numbers (95%) and allergenicity (100-fold). Mite numbers and allergenicity stayed at this low level for 6 weeks. At 16 weeks both mites and allergens showed a slight increase, but were still significantly (P less than 0.001) below pretreatment levels.

Allergens↗

PubMed1980

Effect of a change to mite-free bedding on children with mite-sensitive asthma: a controlled trial.

Twenty-one children with mite-sensitive asthma took part in a crossover randomised controlled trial of mite-free bedding. Each child was issued with a new sleeping bag and pillow for a month, and twice-daily peak flow readings were compared with those obtained during a month in the child's ordinary bedding. Seventeen of the children had higher mean peak flow readings during the period in the mite-free bedding (p < 0.01). The overall improvement was only modest, however, and some mites had appeared in most of the bedding by the end of the trial. New bedding may be helpful to patients with mite-sensitive asthma, but methods are needed to prevent colonisation by mites.

Animals↗

PubMed2001

Characterization of house dust mite and scabies mite allergens by use of canine serum antibodies.

OBJECTIVE: To identify the major allergenic proteins from the 3 main species of dust mites to which dogs react (Dermatophagoides farinae, D. pteronyssinus, and Euroglyphus maynei) and evaluate the potential cross-reactivity of dust mite allergens with antigens from the ectoparasitic mite Sarcoptes scabiei var canis. SAMPLE POPULATION: Sera from 83 dogs with atopic dermatitis. PROCEDURE: Sodium dodecylsulfate-polyacrylamide gel electrophoresis and immunoblotting using serum from atopic dogs was used to identify IgE-binding proteins in extracts of the 4 mite species. RESULTS: Sera of atopic dogs contained IgE against 23, 17, 25, and 17 allergens from D. farinae, D. pteronyssinus, E. maynei, and S. scabiei, respectively. Unlike the situation for humans, the major allergens for dogs are mostly proteins that are larger than 90 kd molecular weight. Dermatophagoides farinae and E. maynei appear to be more allergenic for dogs than is D. pteronyssinus. Some dogs with serum IgE against dust mites also had IgE against antigens of S. scabiei var canis. CONCLUSIONS AND CLINICAL RELEVANCE: Multiple dust mite allergens induce an IgE response in dogs. These allergens are mostly greater than 90 kd molecular weight.

Animals↗

PubMed1988

Comparative analysis of precipitating antibodies in White Rock and Fayoumi hens injected with bovine serum albumin or crude mite extract with resulting effects on northern fowl mite, Ornithonyssus sylviarum (Acari: Macronyssidae) population densities.

Precipitating antibody concentration responses to crude northern fowl mite extract (CME) and bovine serum albumin (BSA) injections were compared in White Rock and Fayoumi hens with two-dimensional immunoelectrophoresis and rocket electrophoresis. The effect of CME injections on northern fowl mite population development was also determined. White Rock and Fayoumi hens developed similar antibody concentrations in response to intramuscular injections of BSA according to serum samples analyzed with two-dimensional immunoelectrophoresis. Rocket electrophoresis analyses of pooled serum samples showed significant differences between slopes of White Rock and Fayoumi pools for CME and BSA injections, suggesting differences in antibody-antigen interactions. Fayoumi hens injected with CME, 78, 50, and 14 days prior to experimental infestation with 2,000 northern fowl mites/bird supported significantly fewer mites than BSA-injected hens, although mite populations were low on both treatment groups. Injections of CME had no effect on mite population development on White Rock hens, even though CME-specific antibodies were detected. Although White Rock hens supported significantly greater mite numbers than Fayoumi hens, the difference was not attributed to anti-CME antibody activity alone.

Animals↗