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PubMed2002

Expression of pair-rule gene homologues in a chelicerate: early patterning of the two-spotted spider mite Tetranychus urticae.

Embryo segmentation has been studied extensively in the fruit fly, Drosophila. These studies have demonstrated that a mechanism acting with dual segment periodicity is required for correct patterning of the body plan in this insect, but the evolutionary origin of the mechanism, the pair-rule system, is unclear. We have examined the expression of the homologues of two Drosophila pair-rule genes, runt and paired (Pax Group III), in segmenting embryos of the two-spotted spider mite (Tetranychus urticae Koch). Spider mites are chelicerates, a group of arthropods that diverged from the lineage leading to Drosophila at least 520 million years ago. In T. urticae, the Pax Group III gene Tu-pax3/7 was expressed during patterning of the prosoma, but not the opisthosoma, in a series of stripes which appear first in even numbered segments, and then in odd numbered segments. The mite runt homologue (Tu-run) in contrast was expressed early in a circular domains that resolved into a segmental pattern. The expression patterns of both of these genes also indicated they are regulated very differently from their Drosophila homologues. The expression pattern of Tu-pax3/7 lends support to the possibility that a pair-rule patterning mechanism is active in the segmentation pathways of chelicerates.

Amino Acid Sequence↗
PubMed2002

Toward elucidating the full spectrum of mite allergens--state of the art.

Our research has focused on the molecular design of immunotherapeutic vaccines and the advancement of mite-allergy diagnosis. Here, we describe the research history of the major group 1 and group 2 allergens, immunoelectrophoretic analyses covering the complete spectrum of mite allergens, our results on allergens with distinctive characteristics (a conjunctival congestion-eliciting antigen [LM2], an immunotherapeutic antigen [HM2] with high efficacy and without definite adverse reactions, and a potent T-cell stimulatory antigen [HM1] with secretion of IFN-gamma), the full spectrum and immunochemical properties of the major and other important mite allergens (including our newly described allergens: a pan-allergen [tropomyosin, group 10], a potent T-cell stimulatory allergen [M-177, apolipophorin, group 14] and its peptide fragments Mag1 and Mag3, a moderate IgE-binding allergen [gelsolin/villin, group 16], an EF-hand Ca2+-binding allergen [group 17], and a less IgE-binding allergen [heat shock protein 70]), and prospects for the development of immunotherapeutic and diagnostic agents.

Journal Article↗
PubMed2006

Effectiveness of house dust mite acaricide tri-n-butyl tin maleate on carpets, fabrics and mattress foam: a standardization of methodology.

The aim of this study was to determine the effectiveness of the acaricide tri-n-butyl tin maleate, industrially applied to samples of carpets, mattress foam, and fabrics used for furniture upholstery, soft toys and shoe uppers. Approximately 100 adult house dust mites of the species Dermatophagoides pteronyssinus were inoculated into a Petri dish containing the sample (a piece of carpet, mattress foam, or fabric), treated with the acaricide, randomly collected. Mite-maintenance culture medium was added on top of each sample. After one, two, three, seven and 30 days of incubation at 25 degrees C and 75% relative humidity, each dish was examined using a 40X stereoscopic microscope (40X). One hundred percent acaricide effectiveness was obtained in treated materials by the end of the 30th-day postinoculation period, under optimal conditions for mite maintenance.

Animals↗
PubMedDate not supplied

[Survival of the mite Acarophenax lacunatus (Cross & Krantz) (Prostigmata: Acarophenacidae) under starvation].

The ability of a natural enemy to tolerate starvation increases its chances to survive in the absence of food, what is an important factor for its success in storage grain environment. The objective of the present work was to assess the survival of Acarophenax lacunatus (Cross & Krantz) in the absence of food. The experiment used individualized physogastric females of A. lacunatus placed in petri dishes (5 cm diameter) and maintained at 20, 25, 28, 30 and 32 degrees C, 50+/-5 % R.H. and 24h scotophase. The number of live mites was recorded every 6h thus assessing the progeny survival without food at different temperatures. The mites died within 60h at the temperatures 30 degrees C and 32 degrees C, while they survived for up to 108h at 20, 25 and 28 degrees C. The mean lethal time for death was 58.6h for the lowest temperatures and 39.3h for the highest temperatures. Thus, A. lacunatus subjected to starvation lived longer under lower temperatures, what is probably due to its lower metabolism. In contrast, the mites survived for about 90h at 28 degrees C, temperature commonly observed in tropical and subtropical climates, what may favor their use as control agents of stored product insects in these regions.

Acaridae↗
PubMed2006

Approaches for sampling the twospotted spider mite (Acari: Tetranychidae) on clementines in Spain.

Tetranychus urticae Koch (Acari: Tetranychidae) is an important pest of clementine mandarins, Citrus reticulata Blanco, in Spain. As a first step toward the development of an integrated crop management program for clementines, dispersion patterns of T. urticae females were determined for different types of leaves and fruit. The study was carried out between 2001 and 2003 in different commercial clementine orchards in the provinces of Castelló and Tarragona (northeastern Spain). We found that symptomatic leaves (those exhibiting typical chlorotic spots) harbored 57.1% of the total mite counts. Furthermore, these leaves were representative of mite dynamics on other leaf types. Therefore, symptomatic leaves were selected as a sampling unit. Dispersion patterns generated by Taylor's power law demonstrated the occurrence of aggregated patterns of spatial distribution (b > 1.21) on both leaves and fruit. Based on these results, the incidence (proportion of infested samples) and mean density relationship were developed. We found that optimal binomial sample sizes for estimating low populations of T. urticae on leaves (up to 0.2 female per leaf) were very large. Therefore, enumerative sampling would be more reliable within this range of T. urticae densities. However, binomial sampling was the only valid method for estimating mite density on fruit.

Animals↗
PubMed2006

Acaricidal activities of some essential oils and their monoterpenoidal constituents against house dust mite, Dermatophagoides pteronyssinus (Acari: Pyroglyphidae).

The acaricidal activities of fourteen essential oils and fourteen of their major monoterpenoids were tested against house dust mites Dermatophagoides pteronyssinus. Five concentrations were used over two different time intervals 24 and 48 h under laboratory conditions. In general, it was noticed that the acaricidal effect based on LC(50) of either essential oils or monoterpenoids against the mite was time dependant. The LC(50) values were decreased by increasing of exposure time. Clove, matrecary, chenopodium, rosemary, eucalyptus and caraway oils were shown to have high activity. As for the monoterpenoids, cinnamaldehyde and chlorothymol were found to be the most effective followed by citronellol. This study suggests the use of the essential oils and their major constituents as ecofriendly biodegradable agents for the control of house dust mite, D. pteronyssinus.

Animals↗
PubMed1992

House-dust mite allergy and eosinophilia in patients with asthma in Rangoon (Yangon).

Skin tests were done by prick and intradermal techniques, using house dust mite (Dermatophagoides pteronyssinus) antigen on 35 patients with early onset asthma, 33 with late onset asthma, 43 with asthma and frequent cough with sputum production (chronic bronchitis) and 30 control subjects. Absolute blood eosinophil and sputum eosinophil (as percentage of leukocytes) counts were performed on each patient. Positive skin tests to house dust mite antigens were significantly more frequent in each of the patient groups (35-75%) than in control subjects (0%), but were not significantly different among the three groups of asthmatics. All three groups of asthmatics had significantly higher mean blood absolute eosinophil counts and sputum eosinophil counts than control subjects, eosinophilia being most frequent in patients with early onset asthma. These findings suggest the importance of exposure to house dust mite antigens in the development of asthma in patients in Rangoon (Yangon), Burma (Myanmar).

Adult↗
PubMed2005

The crystal structure of recombinant proDer p 1, a major house dust mite proteolytic allergen.

Allergy to house dust mite is among the most prevalent allergic diseases worldwide. Most house dust mite allergic patients react to Der p 1 from Dermatophagoides pteronyssinus, which is a cysteine protease. To avoid heterogeneity in the sample used for crystallization, a modified recombinant molecule was produced. The sequence of the proDer p 1 allergen was modified to reduce glycosylation and to abolish enzymatic activity. The resulting rproDer p 1 preparation was homogenous and stable and yielded crystals diffracting to a resolution of 1.61 A. The active site is located in a large cleft on the surface of the molecule. The 80-aa pro-peptide adopts a unique fold that interacts with the active site cleft and a substantial adjacent area on the mature region, excluding access to the cleft and the active site. Studies performed using crossed-line immunoelectrophoresis and IgE inhibition experiments indicated that several epitopes are covered by the pro-peptide and that the epitopes on the recombinant mature molecule are indistinguishable from those on the natural one. The structure confirms previous results suggesting a preference for aliphatic residues in the important P2 position in substrates. Sequence variations in related species are concentrated on the surface, which explains the existence of cross-reacting and species-specific antibodies. This study describes the first crystal structure of one of the clinically most important house dust mite allergens, the cysteine protease Der p 1.

Allergens↗
PubMed1993

Duration of attachment of the chigger, Eutrombicula lipovskyana (Trombiculidae) in mite pockets of Yarrow's spiny lizard, Sceloporus jarrovii (Phrynosomatidae) from Arizona.

Duration of attachment was determined for the chigger, Eutrombicula lipovskyana in mite pockets of the phrynosomatid lizard, Sceloporus jarrovii from Arizona. Eutrombicula lipovskyana remained attached in mite pockets for as long as 52 days. Infestations in other body areas were of shorter duration. The mite Geckobiella texana was also found to infest S. jarrovii.

Animals↗
PubMed2003

Generation and characterization of cDNA clones from Sarcoptes scabiei var. hominis for an expressed sequence tag library: identification of homologues of house dust mite allergens.

Molecular studies on scabies, a disease of considerable human and veterinary significance, have been limited because of the difficulty of obtaining the causative organism Sarcoptes scabiei, the "itch mite." We have used skin from the bedding of crusted scabies patients as a source of mites for the construction of libraries of cDNAs from S. scabiei var. hominis in the bacteriophage lambda vector lambdaZAP express. Sequences of 145 clones established that the libraries predominantly contain sequences from S. scabiei, enabling a major sequencing program to begin. Among those sequenced to date, cDNAs encoding S. scabiei homologues of 3 house dust mite allergens-the M-177 apolipoprotein, glutathione S-transferase, and paramyosin--were identified. The availability of cDNA libraries from S. scabiei var. hominis and S. scabiei var. vulpes and the emerging public sequence databases from both opens up new possibilities in scabies research.

Allergens↗
PubMed2003

House dust-mite allergen and cat allergen variability within carpeted living room floors in domestic dwellings.

Exposure to allergens from house dust-mites (Der p 1) and domestic cats (Fel d 1) is associated with symptom severity in atopic subjects with asthma and rhinitis. Assessment of allergen exposure in the domestic environment is normally determined by measurement from a single floor site. We determined the variability of these allergens and protein throughout the whole living room floor area. Dust samples were collected from 1 m2 areas from 16 carpeted living room floors in Wellington, New Zealand, and analyzed for concentrations of Der p 1 and Fel d 1. Mean coefficients of variation for Der p 1 and Fel d 1 were 53.1% (range: 28.5-136.8) and 65.6% (range: 28.5-131.0), respectively. This study has demonstrated a large variation of house dust-mite and cat allergens within living room floors and thus assessment of a single sampling site may not be representative of an individual's exposure risk. House dust-mite and cat allergen levels from the center of the room, in front of a couch or chair, or from a corner of the room are similar to mean levels from the whole room. These sites may thus be representative of the whole living room floor in large-scale epidemiological studies.

Air Pollution, Indoor↗
PubMedDate not supplied

[The parasite-host specificity of the itch mite Sarcoptes scabiei (Acariformes: Sarcoptidae) in man and animals (a review of the literature)].

The primary parasitic relations between the itch mite Sarcoptes scabiei (L.) and man are confirmed indirectly by the presence in the family Sarcoptidae of close genera, members of which parasitize primates. Judging from the composition of domestic and wild animals-hosts, the source of their infection with S. scabiei was man that gave rise to numerous forms of mites specific to individual species of hosts or their related groups belonging to different taxonomic ranks. Three types of host relations and, accordingly, forms of sarcoptosis are suggested at the infection from an alien host: pseudosarcoptosis, temporary self-curable and typical lingering sarcoptosis. The ways of reinfection, invasiveness of stages of the mite and clinical picture for each form of the disease are analyzed.

Animals↗
PubMed2003

[The relationship between the density of house dust mite allergens in bedroom and the attacks of allergic rhinitis].

OBJECTIVE: To investigate the relationship between the density of house dust mites allergens in bedroom and the attacks of allergic rhinitis in patients sensitive to mite. METHOD: Seventy-five houses (35 patients with allergic rhinitis and 30 healthy controls) were visited for dust sampling from mattresses, sofas, beddings and pillows. Der p1 and Der f1 levels were measured by ELISAs. RESULT: Der p1 and Der f1 levels in healthy control group were significantly higher than levels in patient group(P < 0.05). CONCLUSION: The amount of mite allergens might not be the determining factor for allergic rhinitis sensitization.

Adult↗
PubMed2004

Classification of the sand-mite family Walchiidae (Acariformes: Trombiculoidea).

The priority of Walchiinae Ewing, 1946 based on Walchia Ewing, 1931 or Gahrliepiinae Womersley, 1952 based on Gahrliepia Oudemans, 1912 as Walchia regarded as subgeneric taxon had been a controversy for almost half a century since 1952. Both genera are valid now. Wen (1999) redefined both subfamilial characters and in turn promoted Walchiinae to a full familial status. Walchiidae (Ewing, 1946) Wen, 1999 is characterized by SIF=4B/4Bs/5B/6B-N/B-3/2-2(1)1(0)1(0)0.0000, small to large sized sand-mites, IP=320 - 1220. Scutum is small to large size, extending backward over part of dorsum, and pentagonal with acuminate posterior angle or tongue-shaped. The scutum is never provided with anteromedian setae (AM or vi) and anteromedian projection (A or N=0). Scutal setae have AL and PL pairs basically, frequently in addition with 2 -40 accessories (PPLs), and rarely 1 - 2 pairs of intermedial setae (IM). Sensillae (Sn or sci) are short and expanded. Leg segments are 7.6.6 always without variations. Casting off the anteromedian setae on scutum, increasing the leg segments and reducing the tactile body setae are the plesiomorphic characters of sand-mites, that means Walchiidae in higher advance of evolution than both Trombiculidae (Ewing, 1929) and Leeuwenhoekiidae (Womersley, 1944). It is rationally to unify three families of vertebrate parasitic larvae into a single superfamily, Trombiculoidea nec Welbourn (1991), that separable from superfamily Trombidioidea of arthropod parasitic larvae and standing at most advanced evolution of Parasitengona. Family Walchiidae has 2 subfamilies, Walchiinae Ewing, 1946 sensu Wen 1999 and Gahrliepiinae Womersley, 1952, sensu Wen 1999. Each subfamily contains two tribes, Walchiini (Ewing, 1946) Wen 1984 and Schoengastiellini Wen 1984 for Walchiinae, and Gahrliepiini sensu Wen 1984 and Intermedialiini Wen, 1984 for Gahrliepiinae. Currently this family has 18 genera and 28 subgenera, 248 nominated species and subspecies. Walchiid sand-mites are essentially an Old World family and best developed in the Oriental Region with the center of development in Southeast Asia.

Animals↗
PubMed2001

[The efficacy of controlling of house dusts in attacks of mite sensitive asthmatics].

OBJECTIVE: To study the effect of controlling of house dusts in attacks of mite sensitive asthmatics (DMSA). METHODS: Dust in mattresses, sofas, beddings and pillows were calculated for 43 cases of DMSA every season meanwhile the asthmatic symptoms, amount of drugs taken, PEF value in morning and evening were daily recorded by patients, then the patients were divided into two groups i.e. treatment group (A group, 22 cases) and no treatment group ( B group, 21 cases) randomly. The controlling measures included well-ventilation, washing clothes and bedclothes and catching dust frequently and exposing of clothing or bedclothes in the sun. RESULTS: Correlation was found between house dust density and asthmatic attacks. The number of dust mites was lower after treatment than before in A group [(N/g): spring 62 vs 103, summer 105 vs 132, autumn 163 vs 231, winter 9 vs 13]. Concomitant asthmatic symptoms and amount of drugs taken and total IgE reduced [(0.6 vs 1.6) mg/L] and PEF values or PEF difference improved. CONCLUSION: Control of dust mites growth could alleviate the asthmatic symptoms and decrease the attacks.

Adolescent↗
PubMed2005

[Preliminary survey on concentration of indoor allergens derived from dust mites in residential homes in Shanghai].

OBJECTIVE: To investigate the level of indoor dust mite allergens in residential homes in Shanghai. METHODS: The allergenic proteins, Dff F3 and Der f III (well known allergen) from the whole culture extract of Dermatophagoides farinae were purified by chromatography and sedimentation techniques. Allergic activities of both proteins were identified by skin prick test and RAST. After preparation of specific IgG anti-Dff F3, anti-Der f III, and extraction of indoor allergens from 200 indoor dust samples collected from residential homes, the allergen concentration was measured by sandwich ELISA. Allergen level was expressed in geometric mean and range, the analysis of variance (ANOV) was used to determine the level of significance between groups. RESULTS: Dff F3 and Der f III were demonstrated strongly allergic activities, which can be highly recognized with IgE from sera of the mite-allergic patients with asthma. In the sampled 200 homes, the proportion of homes with Dff F3 level of >10 microg/g was 57.0%, 29.5% for group of 2-10 microg/g, and 13.5% for group of <2 microg/g. The proportion of homes with Der f III level of >10 microg/g was 53.5%, 32.0% for group of 2-10 microg/g, 14.5% for group of <2 microg/g. CONCLUSION: Selected residential homes in Shanghai were found more likely to have high level of dust mite allergens. Dff F3 was identified as the stronger allergic fraction.

Allergens↗
PubMedDate not supplied

[Geographical variation in the species Montivagum dihumerale and speciation in chigger mites (Acari: Trombiculidae)].

Intraspecific morphological variation of the chigger mite species Montivagum dihumerale (Traub et Nadchatram, 1967) is studied. Eco-geographic rules of the variation are revealed. General size of mites is found to be increased along with the rise of the high-mountain character of the landscape in the collection localities. The numbers of idiosomal setae are varied independently from the size parameters and geographically close populations are proved to be the most similar by these characters. At the same time, numbers of the setae of different types play the leading role in the discrimination of closely related Montivagum species, while the eco-geographical rules have not been found in this genus at the level of interspecific differences. As a result, the hypothesis is set up, that a significant degree of isolation of local populations separated from each other by high mountain ranges of the Central Asia is the main factor of speciation in the genus Montivagum. Regional character of this speciation mode is confirmed by the comparison with other chigger mites taxa.

Animals↗
PubMed2006

PCR-based assay to survey for knockdown resistance to pyrethroid acaricides in human scabies mites (Sarcoptes scabiei var hominis).

Permethrin, in the form of a topical cream, is being increasingly used for community-based programs to control endemic scabies. The development of resistance has reduced the use of pyrethroids for the control of many arthropods of economic and health importance. The best recognized form of pyrethroid resistance, known as knockdown resistance or kdr, has been linked to specific mutations in the target of these agents, the para-homologous voltage-sensitive sodium channel gene (Vssc). To develop tools to study resistance to pyrethroid acaricides, we cloned 3711 and 6151 bp, respectively, of cDNA and genomic fragments of the Vssc gene from scabies mite, Sarcoptes scabiei. The sequence encompasses the major polymorphic amino acid residues associated with pyrethroid resistance. A polymerase chain reaction-based strategy has been developed that enables genotyping individual scabies mites. This will facilitate early detection and monitoring of pyrethroid resistance in scabies mite populations under drug selection pressure.

Amino Acid Sequence↗