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At least 19 recordsLinked to original sources
PubMed2000

Pirimiphos-methyl resistance in two stored product mites, Acarus siro and Acarus farris, as detected by impregnated paper bioassay and esterase activity assays.

The response to pirimiphos-methyl, in one strain of Acarus farris and two strains of Acarus siro, was assessed using an impregnated filter paper bioassay and by the selection of adults following exposure to pirimiphos-methyl. It was concluded that one of the strains of A. siro was resistant to pirimiphos-methyl and that a major resistance mechanism was involved. The second strain of A. siro gave a response similar to that of a laboratory strain unexposed to organophosphates and was considered to be susceptible. The A. farris strain responded to selection at the ED50 but not at the ED99, and it was concluded that a minor resistance mechanism is present in this strain. Assays of esterase activity were used to attempt to identify the biochemical mechanisms involved in the resistance detected by the bioassays. The A. farris and susceptible A. siro strains showed similar levels of esterase activity but the esterase activity of the resistant A. siro strain was significantly greater. An increase in esterase activity followed selection of both the A. farris strain and the resistant A. siro strain. An acetylcholinesterase assay showed no significant difference between the susceptible and pirimiphos-methyl selected strains of A. siro. The results suggest that esterases are involved in the resistance to pirimiphos-methyl found in A. siro and A. farris but that in A. siro, at least, other mechanisms may also be present.

Acetylcholinesterase↗
PubMed2004

Molecular systematics of Acarus siro s. lat., a complex of stored food pests.

The astigmatid mite Acarus siro (Linnaeus 1758) is an important agricultural pest and environmental allergen. However, it is likely that many mites described in the literature as A. siro, collected from both outdoor and stored product habitats, may belong to one of its sibling species, A. farris [Ent. Ber. Amst. 2 (26) (1905) 20] or A. immobilis [Bull. Br. Mus. Nat. Hist. 11 (1964a) 413; Acarologia. 6 (Suppl) (1964) 101]. The three species are difficult to separate morphologically, gene exchange between some of them is possible and, although each species displays environmental preferences, they occur together in some environments. This raises a question about their separate species status. In a pilot study, we investigated whether genetic data supported the separate species status of these forms. Both nuclear (the second internal transcribed spacer region [ITS-2] of the ribosomal cistron) and mitochondrial (cytochrome oxidase subunit I, mtcoxI hereafter) loci were employed for this purpose. Mtcox1 data does not conflict the differentiation into three separate species and while the ITS2 data were problematic for this group of mites it suggested that a congener, Acarus gracilis [Ann. Mag. Nat. Hist. 10 (1957) 753], is basal to the A. siro species complex.

Animals↗
PubMedDate not supplied

Comparison of skin test results obtained with different dust, Dermatophagoides; Acarus siro and spider extracts.

The authors describe the comparative analysis of skin tests performed in 87 asthmatic children with extracts of house dust, grain dust and different arthropodes beloging to the Arachidaegenus. Most of these patients were living in traditional agricultural environment. Reactions to the Acarus siro and grain dust (Sevac) extracts gave significant correlation, whereas house dust did not show this agreement. Extracts from spiders (Aranidae) caused often, in 40% of asthmatic children, positive skin reaction; that was the same frequency as with Dermatophagoides, nevertheless the correlation was only partial. The authours conclude that Acarus siro and antigenically related mites are the main allergizing component of grain dust; excretes of spiders display a comparable allergizing factor in house dust as do Pyroglyphid mites in this area.

Allergens↗
PubMed1990

Anatomy and ultrastructure of the reproductive systems of Acarus siro (Acari: Acaridae).

Anatomy and ultrastructure of the female and male reproductive system in Acarus siro L. were investigated by light and electron microscopy. The female system consists of paired ovaries of nutrimentary type in which oogonia and oocytes are connected by bridges with a large central cell. The oviducts empty into the uterus, which passes into preoviporal duct lined by cuticle, and opening as a longitudinal slit (oviporus). An elongated accessory gland composed of one type of secretory cell is located along each oviduct. The copulatory opening occurs at the posterior margin of the body and leads, via the inseminatory canal, to the receptaculum seminis, consisting of the basal and saccular part. Both inseminatory canal and basal part of receptaculum seminis are lined by cuticle, whereas the wall of the sac is formed by cells covered only by long, numerous microvilli. The basal part of the receptaculum seminis joins the ovaries via two lumenless transitory cones. The male reproductive system contains paired testes, in which spermatogonia tightly surround the central cell. The proximal part of the paired vasa deferentia serves as a sperm reservoir, while the distal one has a glandular character. An unpaired, cuticle-lined ejaculatory duct opens into the apex of the aedeagus. The single accessory gland is located asymmetrically at the level of, or slightly posterior to, coxae IV. The structure of the genital papillae, which are topographically related to the genital opening in both sexes, is also briefly described.

Animals↗
PubMed1991

Energy budget of the grain mite, Acarus siro (Acari: Acaridae).

Immature individuals of Acarus siro L. ingest a total of 0.1408 J of food energy, 58.5% of which is consumed by the deutonymph, 27.1% by the protonymph and only 14.1% by the larva. The total ingestion is much greater (2.8169 J +/- 0.0981 SE). Much energy, 0.7031 J +/- 0.0231 SE, is used for egg production, which is concentrated in the first 20 days of adult life. Assimilation efficiency during this period varies from 63 to 71%. Most energy ingested between the 20th and 40th days of adult life is used in biomass production, and biomass increases significantly up to the 30th day. Afterwards, old individuals expend a large amount of assimilated energy on respiration due to the increased cost of maintenance.

Animals↗
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↗
PubMed2005

In vitro and in vivo inhibition of alpha-amylases of stored-product mite Acarus siro.

The stored-product mites are the most abundant and frequent group of pests living on the stored food products in Europe. They endanger public health since they produce allergens and transmit mycotoxin-producing fungi. Novel acaricidal compounds with inhibitory effects on the digestive enzymes of arthropods are a safe alternative to the traditional neurotoxic pesticides used for control of the stored-product pests. In this work, we explored the properties of acarbose, the low molecular weight inhibitor of alpha-amylases (AI), as a novel acaricide candidate for protection of the stored products from infestation by Acarus siro (Acari: Acaridae). In vitro analysis revealed that AI blocked efficiently the enzymatic activity of digestive amylases of A. siro, and decreased the physiological capacity of mite's gut in utilizing a starch component of grain flour. In vivo experiments showed that AI suppressed the population growth of A. siro. The mites were kept for three weeks on experimental diet enriched by AI in concentration range of 0.005 to 0.25%. Population growth of A. siro was negatively correlated with the content of AI in the treated diet with a half-population dose of 0.125%. The suppressive effect of AIs on stored-product mites is discussed in the context of their potential application in GMO crops.

Acarbose↗
PubMed2006

Laboratory studies on the use of two new arenas to evaluate the impact of the predatory mites Blattisocius tarsalis and Cheyletus eruditus on residual populations of the stored product mite Acarus siro.

Residual populations of storage mites sheltering in crevices and cracks escape conventional control treatments and are implicated in the infestation of newly harvested grain. In a series of 24 h laboratory tests, the performance of solitary adults of two predatory mite species, Cheyletus eruditus (Schrank) and Blattisocius tarsalis (Berlese), were assessed for controlling small numbers of the flour mite Acarus siro (L.). Tests were carried out in the presence or absence of prey refuges or grain debris to afford shelter to the flour mites. While C. eruditus had a significant effect on the motile stages of A. siro, in contrast B. tarsalis had a significant effect on the eggs. The maximum percentage of motile stages of A. siro eaten by C. eruditus was 82%, whereas the minimum percentage of A. siro eggs eaten by B. tarsalis was 99%. While the performance of C. eruditus in predating on motile stages of the flour mite was hindered by the presence of the prey refuge (38% eaten) and grain debris (25% eaten), the performance of B. tarsalis in predating on flour mite eggs was unaffected (100% eaten in presence of prey refuge or grain debris). In prolonged exposures (36 days) the performance of 2, 4 or 8 adult predators, either a single species or a combination of both, was assessed for their ability to control a population of the flour mite developing up to F(2) from an initial inoculum of 80 females and 20 males, allowed to oviposit for 72 h in the absence of predatory mites. The maximum reduction in prey population of 80% was achieved with eight B. tarsalis. Combining the two predatory species did not enhance the reduction of A. siro population.

Animals↗
PubMed2001

Allergenic cross-reactivity between the nematode Anisakis simplex and the dust mites Acarus siro, Lepidoglyphus destructor, Tyrophagus putrescentiae, and Dermatophagoides pteronyssinus.

BACKGROUND: The nematode Anisakis simplex is a common parasite on fish and other seafood. It is considered to be a food allergen and to induce IgE-mediated reactions. Allergenic cross-reactivity between A. simplex and other nematodes has been reported, as has cross-reactivity with arthropods: red mosquito larvae and German cockroach. We have here studied the allergenic relationship between A. simplex and four different dust-mite species. METHODS: Serum samples collected from 69 farmers allergic to dust mites were analyzed for IgE to A. simplex by CAP FEIA. Allergenic cross-reactivity between A. simplex and dust mites was studied in two of the sera by CAP FEIA and immunoblotting inhibition. RESULTS: We found that 14/69 farmers had detectable levels of IgE antibodies to A. simplex. The IgE response in CAP FEIA to A. simplex was inhibited to various degrees in the two studied sera by extracts of the dust mites Acarus siro, Lepidoglyphus destructor, Tyrophagus putrescentiae, and Dermatophagoides pteronyssinus. In the reverse inhibition experiment, extract of A. simplex inhibited the response in both sera to A. siro and T. putrescentiae, but not to L. destructor. The IgE binding to D. pteronyssinus was inhibited in one of the two sera. In blotting inhibition experiments, the IgE binding to several allergens in A. simplex was inhibited by each of the four mite extracts, especially by A. siro and T. putrescentiae, which completely inhibited the IgE binding to several allergens. CONCLUSION: The results show allergenic cross-reactivity between several allergens in A. simplex and four dust-mite species. The clinical significance of this cross-reactivity remains to be evaluated.

Animals↗
PubMed1992

Effects of radiation on spermatogenesis in Acarus siro L. (Acari: Acaridae).

Modifications of spermatogenesis and anatomy of male reproductive tracts caused by radiation (fast electrons) are described in Acarus siro and compared with data from other arthropod taxa. Radiation induced severe changes in gonial cells, including dilatation of endoplasmic reticulum and disruption of mitochondrial cristae. The latter sometimes created roundish myelin structures inside the mitochondrial matrix. Damage in developing cells caused an interruption of spermatogenesis and reduced the number of spermatids produced; high doses can cause sterility.

Animals↗
PubMed2004

Proteolytic activities in body and faecal extracts of the storage mite, Acarus farris.

Trypsin, chymotrypsin, cathepsins B and D, aminopeptidase and carboxypeptidases A and B were detected in body extracts of the storage mite Acarus farris (Oudemans) (Astigmata: Acaridae). Faeces-enriched medium exhibited higher (10-50-fold) specific protease activity rates than those measured with mite body extracts for trypsin, chymotrypsin and carboxypeptidases A and B, suggesting that they are involved in mite digestion. However, the activity of cathepsin B was only three-fold higher in faecal than in body extracts, indicating that its presence in the lumen of the digestive tract is low compared to that of serine proteases. The activity of aminopeptidases was higher in mite bodies, indicating that they might be membrane bound. Cathepsin D activity was only detected in body extracts, indicating that this enzyme is not a digestive protease in this species. Zymograms resolved three major bands of gelatinolytic activity, but at least one protease form was only present in body extracts. Protease inhibitors of different specificity were tested in vivo to establish their potential as control agents. The development of A. farris was significantly retarded when the immature stages were fed on artificial diet containing inhibitors of serine and cysteine proteases and aminopeptidases, whereas no such effect was found with inhibitors of aspartyl proteases and carboxypeptidases. Interestingly, the most significant effects on A. farris occurred when a combination of inhibitors targeting different enzyme classes was supplied mixed in the diet, suggesting a synergistic toxicity. Several plant lectins were also tested, but only wheat germ agglutinin and concanavalin-A affected development.

Acaridae↗
PubMed1994

Allergenic characterization of Acarus siro and Tyrophagus putrescentiae and their crossreactivity with Lepidoglyphus destructor and Dermatophagoides pteronyssinus.

Allergenic components in extracts of Acarus siro and Tyrophagus putrescentiae were identified by sodium dodecyl sulphate-polyacrylamide (SDS-PAGE) and immunoblotting. Five and four allergenic components, respectively, were visualized with sera from farmers sensitized to storage mites. The highest frequency of IgE-binding was to a 15 kDa component of A. siro (7/9 sera) and a 16 kDa component of T. putrescentiae (23/29 sera). The allergenic crossreactivity of A. siro and T. putrescentiae with Lepidoglyphus destructor and Dermatophagoides pteronyssinus was studied with an immunoblotting inhibition technique. Crossreactivity between D. pteronyssinus on the one hand and A. siro and T. putrescentiae on the other, was shown, as the IgE reactivity to a 25 kDa component of D. pteronyssinus was inhibited to the same degree by extracts of A. siro, T. putrescentiae and D. pteronyssinus. However, D. pteronyssinus was a poor inhibitor of the allergenic components of A. siro and T. putrescentiae. Strong cross-reactivity was also shown between L. destructor and the allergenic components of A. siro and T. putrescentiae, while the latter mite species only to a very low degree inhibited the allergenic components of L. destructor.

Allergens↗
PubMed1998

Prevalence of sensitization to the storage mites Acarus siro, Tyrophagus putrescentiae, and Lepidoglyphus destructor in allergic patients with different degrees of sensitization to the house-dust mite Dermatophagoides pteronyssinus.

The prevalence of sensitization to the storage mites Acarus siro (AS), Tyrophagus putrescentiae (TP), and Lepidoglyphus destructor (LD) was studied in 250 sera of patients with different degrees of sensitization to the house-dust mite Dermatophagoides pteronyssinus (DP) by measuring IgE binding to extracts of the storage mites. Additionally, allergenic cross-reactivity between DP and the storage mite species was studied by RAST inhibition with five individual sera (and a pool of these sera) with moderate IgE levels to all three storage mites and to DP. Increased serum IgE to storage mites was found in 46% of the 200 patients sensitized to DP. Increased prevalence rates of IgE titers to storage mites were associated with higher IgE levels to DP. In 50 sera without sensitization to DP, only five sera showed increased IgE to one of the storage mites. Extracts of TP almost completely inhibited the IgE binding to AS, and vice versa. DP inhibited IgE binding to all storage mites up to 60%, whereas IgE binding to DP was only minimally inhibited by extracts of storage mites. In conclusion, cosensitization to storage mites is a frequent finding in patients sensitized to DP. Although this is largely the result of cross-reactivity between different mite species, it may nevertheless be of clinical significance in patients exposed to storage mites.

Adult↗
PubMed1997

Dermatosis associated with Acarus farris in gerbils.

A dermatosis associated with Acarus farris is described in a group of three gerbils. Large number of an immature stage (hypopi) of the mite were found on hair pluck samples. Treatment and changes in management led to a resolution of the problem.

Animals↗
PubMed1999

Identification and characterisation of two allergens from the dust mite Acarus siro, homologous with fatty acid-binding proteins.

BACKGROUND: Dust mites are a major cause of allergic disease worldwide. The dust mite Acarus siro is an inducer of occupational allergy among farmers, but sensitisation has also been found in non-farming populations. METHODS: A degenerate primer was designed to the N-terminal amino acid sequence of a 15-kD IgE-binding protein in A. siro extract. The cDNA sequence was obtained by using reverse transcriptase polymerase chain reaction, standard cloning and sequencing techniques. The protein was expressed in Escherichia coli with a 6-histidine tag at its C-terminus. Immunoblotting of the recombinant protein and whole extract was performed using patient sera. RESULTS AND CONCLUSION: 15 and 17-kD allergens were identified in a fraction of A. siro extract. The cDNA of the 15-kD allergen was isolated, cloned and sequenced and the allergen was expressed as a recombinant protein. The calculated molecular weight of the cDNA-encoded protein is 14.2 kD. The predicted amino acid sequence has one potential N-glycosylation site at position 4-6 and a cytosolic fatty acid-binding protein signature at position 5-22. The protein has 64% sequence identity with Blo t 13, an allergen from the dust mite Blomia tropicalis, as well as homology with several other fatty acid-binding proteins (FABPs) from different organisms. The allergen was named Aca s 13 and was recognised strongly by 3 of 13 (23%) of the subjects investigated. The amino acid sequence of the 17-kD protein was partly determined and it also showed high sequence homology with Blo t 13 and FABPs.

Allergens↗
PubMedDate not supplied

[Immunotherapy with acarus extract in children under the age of 5 years].

BACKGROUND: Specific immunotherapy with allergens is the only treatment capacite of modifying the natural course of allergic diseases. Although its effectiveness is higher when started in early stages, WHO guidelines still consider age under 5 years as relative contraindication.A review of a group of 22 children starting immunotherapy before the age of 5 years in a pediatric allergy unit was attempted to assess the effectiveness and safety of this treatment. METHODOLOGY AND RESULTS: Clinical charts of 22 children with house dust mite asthma starting conventional immunotherapy before the age of 5 years were reviewed. In all cases, biologically standardized extracts and conventional subcutaneous schedules have been used and administration was performed in a hospital setting. Effectiveness and safety were evaluated by clinical scores. The average treatment period was 16.95 ( 10.12) months. Systemic reactions (moderate) were observed in 7 children and local reactions in 5. Children treated for more than 1 year (15 patients) showed a decrease in the number of yearly acute exacerbations (from 5.13 to 2.57) and in hospital admissions (from 5 to 2 children). In 10 patients, drug requirements for bronchial asthma were reduced. CONCLUSION: The clinical data if this study suggest that house dust mite specific immunotherapy under hospital control can be begun in young children with good tolerance and clinical improvement.

Age Factors↗