Identification and biosynthesis of an aggregation pheromone of the storage mite Chortoglyphus arcuatus.

In an effort to identify new pheromones from mites, the headspace of undisturbed colonies of the storage mite Chortoglyphus arcuatus was analyzed by GC-MS by use of a closed-loop stripping apparatus (CLSA) or solid-phase microextraction (SPME). The major compound emitted from the mites is (4R,6R,8R)-4,6,8-trimethyldecan-2-one (4R,6R,8R-8). The structure was elucidated by analysis of the mass spectrum, synthesis of authentic samples, and gas chromatography on a chiral phase. Bioassays show that this compound, for which we propose the trivial name chortolure, is an aggregation pheromone for both sexes of this species. Several related compounds are released in smaller amounts by the mites. The alarm pheromones of these mites, neral and geranial, can only be found in total extracts of the mites, in which 8 occurs only in minute amounts. The method of sampling is therefore crucial for pheromone identification. Feeding experiments with deuterated propionate showed that chortolure is a polyketide, formed by successive addition of four propionate units to an acetate starter.

Sensitization to different mite species in German farmers: in vitro analyses.

Allergic airway diseases are often caused by house dust mites (HDM) and storage mites (SM), respectively, and we were recently able to demonstrate that symptomatic German farmers are frequently sensitized to different mite species. The present study aimed to obtain information on the protein and immunobiochemical characteristics of the extracts of the following mites: Dermatophagoides pteronyssinus, Dermatophagoides farinae, Acarus siro, Acarus farris, Lepidoglyphus destructor, Tyrophagus putrescentiae, Blomia tjibodas, Blomia topicalis, Blomia kulagini, Glycyphagus domesticus, Thyreophagus entomophagus, and Cheyletus eruditus. Specific IgE determinations were performed with EAST. The protein patterns of the mite extracts were studied by SDS-PAGE estimating the weighted-average molecular weights of the proteins. Using the Western blot technique, we determined the allergen pattern in several mite extracts. The allergens in each extract were classified in terms of the frequency of sensitization as major, intermediate, and minor allergens using allergograms. As already reported, a positive EAST to at least one mite was measured in 31/86 patients, and most sera were positive with several mite species. The majority of the mite extracts exhibited a very complex protein pattern according to SDS-PAGE. An allergen was found in Western blots of nearly all species equivalent to a molecular weight of 14 to 15 kD. This was, in our opinion, the first time that this particular allergen was detected in Blomia tjibodas and Glycyphagus domesticus. In conclusion, using EAST we were able to show that 36% of the German farmers tested were sensitized to SM. All mite extracts showed a complex protein pattern in the molecular weight range -95 kD to -10 kD. A common allergen band in the region of -14 to -15 kD was found in the majority of the mites studied, and it can be assumed that this corresponds with the group 2 allergen.

In vivo and in vitro sensitization to domestic mites in German urban and rural allergic patients.

Sensitization to domestic mites is common in Germany. The main objectives of this study were (1) to establish the rate of skin test sensitivity to Dermatophagoides pteronyssinus, Acarus siro, Lepidoglyphus destructor, and Tyrophagus putrescentiae in 512 consecutive patients evaluated for upper and/or lower respiratory complaints; (2) to verify how many of the patients with a positive skin test to at least one of the three storage mites were also skin test positive to D. pteronyssinus; and (3) to verify how many of the patients with at least one positive skin test to one of the storage mites previously mentioned were also sensitized, in vitro, to other mite species. A total of 512 consecutive patients with rhinitis and/or asthma, living in urban or rural areas of central Germany were skin tested with extracts of D. pteronyssinus, A. siro, L. destructor, and T. putrescentiae. In addition, specific IgE determinations to Euroglyphus maynei, Blomia tropicalis, Blomia tjibodas, Blomia kulagini, and Gohieria fusca were conducted in those individuals with a positive skin test to at least one of the storage mites used in skin testing. Of the 512 patients, 103 (20.1%; 77 urban dwellers and 26 farmers) reacted to at least one of the storage mites. From this latter group, 88 individuals (85.4%) also skin tested positive to D. pteronyssinus. In vitro specific IgE determinations revealed a high rate of sensitization to the other mite species studied. We conclude that sensitization to storage mites in Germany is frequently associated with sensitivity to D. pteronyssinus. Overall, skin test sensitivity to storage mites was greater in rural than in city dwellers. In vitro sensitization to B. tjibodas was also significantly greater in rural than in city dwellers.